X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=vnet%2Fvnet%2Fdevices%2Fvirtio%2Fvhost-user.c;h=6741e932131c2e765f55c4bf2f5bcf2ec7c21a79;hb=d3eb90ecfc1711805deab241a63edd2da2203ef8;hp=1d7180c6bed810f0fdc8560f7d7d9af1c10637f4;hpb=f3bd5716c1e2dfb1063a0abb0b2fdaf0bccf159f;p=vpp.git diff --git a/vnet/vnet/devices/virtio/vhost-user.c b/vnet/vnet/devices/virtio/vhost-user.c index 1d7180c6bed..6741e932131 100644 --- a/vnet/vnet/devices/virtio/vhost-user.c +++ b/vnet/vnet/devices/virtio/vhost-user.c @@ -64,6 +64,29 @@ #define DBG_VQ(args...) #endif +/* + * When an RX queue is down but active, received packets + * must be discarded. This value controls up to how many + * packets will be discarded during each round. + */ +#define VHOST_USER_DOWN_DISCARD_COUNT 256 + +/* + * When the number of available buffers gets under this threshold, + * RX node will start discarding packets. + */ +#define VHOST_USER_RX_BUFFER_STARVATION 32 + +/* + * On the receive side, the host should free descriptors as soon + * as possible in order to avoid TX drop in the VM. + * This value controls the number of copy operations that are stacked + * before copy is done for all and descriptors are given back to + * the guest. + * The value 64 was obtained by testing (48 and 128 were not as good). + */ +#define VHOST_USER_RX_COPY_THRESHOLD 64 + #define UNIX_GET_FD(unixfd_idx) \ (unixfd_idx != ~0) ? \ pool_elt_at_index (unix_main.file_pool, \ @@ -86,7 +109,8 @@ vlib_node_registration_t vhost_user_input_node; #define foreach_vhost_user_tx_func_error \ _(NONE, "no error") \ - _(NOT_READY, "vhost user state error") \ + _(NOT_READY, "vhost vring not ready") \ + _(DOWN, "vhost interface is down") \ _(PKT_DROP_NOBUF, "tx packet drops (no available descriptors)") \ _(PKT_DROP_NOMRG, "tx packet drops (cannot merge descriptors)") \ _(MMAP_FAIL, "mmap failure") \ @@ -587,14 +611,19 @@ vhost_user_if_disconnect (vhost_user_intf_t * vui) } #define VHOST_LOG_PAGE 0x1000 -always_inline void -vhost_user_log_dirty_pages (vhost_user_intf_t * vui, u64 addr, u64 len) +static_always_inline void +vhost_user_log_dirty_pages_2 (vhost_user_intf_t * vui, + u64 addr, u64 len, u8 is_host_address) { if (PREDICT_TRUE (vui->log_base_addr == 0 || !(vui->features & (1 << FEAT_VHOST_F_LOG_ALL)))) { return; } + if (is_host_address) + { + addr = (u64) map_user_mem (vui, (uword) addr); + } if (PREDICT_FALSE ((addr + len - 1) / VHOST_LOG_PAGE / 8 >= vui->log_size)) { DBG_SOCK ("vhost_user_log_dirty_pages(): out of range\n"); @@ -610,6 +639,12 @@ vhost_user_log_dirty_pages (vhost_user_intf_t * vui, u64 addr, u64 len) } } +static_always_inline void +vhost_user_log_dirty_pages (vhost_user_intf_t * vui, u64 addr, u64 len) +{ + vhost_user_log_dirty_pages_2 (vui, addr, len, 0); +} + #define vhost_user_log_dirty_ring(vui, vq, member) \ if (PREDICT_FALSE(vq->log_used)) { \ vhost_user_log_dirty_pages(vui, vq->log_guest_addr + STRUCT_OFFSET_OF(vring_used_t, member), \ @@ -1185,10 +1220,16 @@ vhost_user_init (vlib_main_t * vm) vum->coalesce_frames = 32; vum->coalesce_time = 1e-3; - vec_validate_aligned (vum->rx_buffers, tm->n_vlib_mains - 1, - CLIB_CACHE_LINE_BYTES); vec_validate (vum->cpus, tm->n_vlib_mains - 1); + vhost_cpu_t *cpu; + vec_foreach (cpu, vum->cpus) + { + /* This is actually not necessary as validate already zeroes it + * Just keeping the loop here for later because I am lazy. */ + cpu->rx_buffers_len = 0; + } + /* find out which cpus will be used for input */ vum->input_cpu_first_index = 0; vum->input_cpu_count = 1; @@ -1217,15 +1258,6 @@ vhost_user_exit (vlib_main_t * vm) VLIB_MAIN_LOOP_EXIT_FUNCTION (vhost_user_exit); -typedef struct -{ - u16 qid; /** The interface queue index (Not the virtio vring idx) */ - u16 device_index; /** The device index */ - u32 virtio_ring_flags; /** Runtime queue flags **/ - u16 first_desc_len; /** Length of the first data descriptor **/ - virtio_net_hdr_mrg_rxbuf_t hdr; /** Virtio header **/ -} vhost_trace_t; - static u8 * format_vhost_trace (u8 * s, va_list * va) { @@ -1285,7 +1317,7 @@ vhost_user_rx_trace (vhost_trace_t * t, if (txvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT) { t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_INDIRECT; - //Header is the first here + /* Header is the first here */ hdr_desc = map_guest_mem (vui, txvq->desc[desc_current].addr, &hint); } if (txvq->desc[desc_current].flags & VIRTQ_DESC_F_NEXT) @@ -1324,6 +1356,110 @@ vhost_user_send_call (vlib_main_t * vm, vhost_user_vring_t * vq) vq->int_deadline = vlib_time_now (vm) + vum->coalesce_time; } +static_always_inline u32 +vhost_user_input_copy (vhost_user_intf_t * vui, vhost_copy_t * cpy, + u16 copy_len, u32 * map_hint) +{ + void *src0, *src1, *src2, *src3; + if (PREDICT_TRUE (copy_len >= 4)) + { + if (PREDICT_FALSE (!(src2 = map_guest_mem (vui, cpy[0].src, map_hint)))) + return 1; + if (PREDICT_FALSE (!(src3 = map_guest_mem (vui, cpy[1].src, map_hint)))) + return 1; + + while (PREDICT_TRUE (copy_len >= 4)) + { + src0 = src2; + src1 = src3; + + if (PREDICT_FALSE + (!(src2 = map_guest_mem (vui, cpy[2].src, map_hint)))) + return 1; + if (PREDICT_FALSE + (!(src3 = map_guest_mem (vui, cpy[3].src, map_hint)))) + return 1; + + CLIB_PREFETCH (src2, 64, LOAD); + CLIB_PREFETCH (src3, 64, LOAD); + + clib_memcpy ((void *) cpy[0].dst, src0, cpy[0].len); + clib_memcpy ((void *) cpy[1].dst, src1, cpy[1].len); + copy_len -= 2; + cpy += 2; + } + } + while (copy_len) + { + if (PREDICT_FALSE (!(src0 = map_guest_mem (vui, cpy->src, map_hint)))) + return 1; + clib_memcpy ((void *) cpy->dst, src0, cpy->len); + copy_len -= 1; + cpy += 1; + } + return 0; +} + +/** + * Try to discard packets from the tx ring (VPP RX path). + * Returns the number of discarded packets. + */ +u32 +vhost_user_rx_discard_packet (vlib_main_t * vm, + vhost_user_intf_t * vui, + vhost_user_vring_t * txvq, u32 discard_max) +{ + /* + * On the RX side, each packet corresponds to one descriptor + * (it is the same whether it is a shallow descriptor, chained, or indirect). + * Therefore, discarding a packet is like discarding a descriptor. + */ + u32 discarded_packets = 0; + u32 avail_idx = txvq->avail->idx; + u16 qsz_mask = txvq->qsz - 1; + while (discarded_packets != discard_max) + { + if (avail_idx == txvq->last_avail_idx) + goto out; + + u16 desc_chain_head = + txvq->avail->ring[txvq->last_avail_idx & qsz_mask]; + txvq->last_avail_idx++; + txvq->used->ring[txvq->last_used_idx & qsz_mask].id = desc_chain_head; + txvq->used->ring[txvq->last_used_idx & qsz_mask].len = 0; + vhost_user_log_dirty_ring (vui, txvq, + ring[txvq->last_used_idx & qsz_mask]); + txvq->last_used_idx++; + discarded_packets++; + } + +out: + CLIB_MEMORY_BARRIER (); + txvq->used->idx = txvq->last_used_idx; + vhost_user_log_dirty_ring (vui, txvq, idx); + return discarded_packets; +} + +/* + * In case of overflow, we need to rewind the array of allocated buffers. + */ +static void +vhost_user_input_rewind_buffers (vlib_main_t * vm, + vhost_cpu_t * cpu, vlib_buffer_t * b_head) +{ + u32 bi_current = cpu->rx_buffers[cpu->rx_buffers_len]; + vlib_buffer_t *b_current = vlib_get_buffer (vm, bi_current); + b_current->current_length = 0; + b_current->flags = 0; + while (b_current != b_head) + { + cpu->rx_buffers_len++; + bi_current = cpu->rx_buffers[cpu->rx_buffers_len]; + b_current = vlib_get_buffer (vm, bi_current); + b_current->current_length = 0; + b_current->flags = 0; + } +} static u32 vhost_user_if_input (vlib_main_t * vm, @@ -1332,26 +1468,28 @@ vhost_user_if_input (vlib_main_t * vm, u16 qid, vlib_node_runtime_t * node) { vhost_user_vring_t *txvq = &vui->vrings[VHOST_VRING_IDX_TX (qid)]; - vhost_user_vring_t *rxvq = &vui->vrings[VHOST_VRING_IDX_RX (qid)]; - uword n_rx_packets = 0, n_rx_bytes = 0; - uword n_left; + u16 n_rx_packets = 0; + u32 n_rx_bytes = 0; + u16 n_left; u32 n_left_to_next, *to_next; - u32 next_index = 0; - u32 next0; - uword n_trace = vlib_get_trace_count (vm, node); + u32 next_index = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT; + u32 n_trace = vlib_get_trace_count (vm, node); u16 qsz_mask; - u32 cpu_index, rx_len, drops, flush; - f64 now = vlib_time_now (vm); - u32 map_guest_hint_desc = 0; - u32 map_guest_hint_indirect = 0; - u32 *map_guest_hint_p = &map_guest_hint_desc; + u32 map_hint = 0; + u16 cpu_index = os_get_cpu_number (); + u16 copy_len = 0; - /* do we have pending interrupts ? */ - if ((txvq->n_since_last_int) && (txvq->int_deadline < now)) - vhost_user_send_call (vm, txvq); + { + /* do we have pending interrupts ? */ + vhost_user_vring_t *rxvq = &vui->vrings[VHOST_VRING_IDX_RX (qid)]; + f64 now = vlib_time_now (vm); + + if ((txvq->n_since_last_int) && (txvq->int_deadline < now)) + vhost_user_send_call (vm, txvq); - if ((rxvq->n_since_last_int) && (rxvq->int_deadline < now)) - vhost_user_send_call (vm, rxvq); + if ((rxvq->n_since_last_int) && (rxvq->int_deadline < now)) + vhost_user_send_call (vm, rxvq); + } if (PREDICT_FALSE (txvq->avail->flags & 0xFFFE)) return 0; @@ -1371,82 +1509,65 @@ vhost_user_if_input (vlib_main_t * vm, * client must not supply any new RX packets, but must process * and discard any TX packets." */ - - txvq->last_avail_idx = txvq->last_used_idx = txvq->avail->idx; - CLIB_MEMORY_BARRIER (); - txvq->used->idx = txvq->last_used_idx; - vhost_user_log_dirty_ring (vui, txvq, idx); - vhost_user_send_call (vm, txvq); + vhost_user_rx_discard_packet (vm, vui, txvq, + VHOST_USER_DOWN_DISCARD_COUNT); return 0; } if (PREDICT_FALSE (n_left == txvq->qsz)) { - //Informational error logging when VPP is not receiving packets fast enough + /* + * Informational error logging when VPP is not + * receiving packets fast enough. + */ vlib_error_count (vm, node->node_index, VHOST_USER_INPUT_FUNC_ERROR_FULL_RX_QUEUE, 1); } qsz_mask = txvq->qsz - 1; - cpu_index = os_get_cpu_number (); - drops = 0; - flush = 0; if (n_left > VLIB_FRAME_SIZE) n_left = VLIB_FRAME_SIZE; - /* Allocate some buffers. - * Note that buffers that are chained for jumbo - * frames are allocated separately using a slower path. - * The idea is to be certain to have enough buffers at least - * to cycle through the descriptors without having to check for errors. - * For jumbo frames, the bottleneck is memory copy anyway. + /* + * For small packets (<2kB), we will not need more than one vlib buffer + * per packet. In case packets are bigger, we will just yeld at some point + * in the loop and come back later. This is not an issue as for big packet, + * processing cost really comes from the memory copy. */ - if (PREDICT_FALSE (!vum->rx_buffers[cpu_index])) + if (PREDICT_FALSE (vum->cpus[cpu_index].rx_buffers_len < n_left + 1)) { - vec_alloc (vum->rx_buffers[cpu_index], 2 * VLIB_FRAME_SIZE); - - if (PREDICT_FALSE (!vum->rx_buffers[cpu_index])) - flush = n_left; //Drop all input - } - - if (PREDICT_FALSE (_vec_len (vum->rx_buffers[cpu_index]) < n_left)) - { - u32 curr_len = _vec_len (vum->rx_buffers[cpu_index]); - _vec_len (vum->rx_buffers[cpu_index]) += + u32 curr_len = vum->cpus[cpu_index].rx_buffers_len; + vum->cpus[cpu_index].rx_buffers_len += vlib_buffer_alloc_from_free_list (vm, - vum->rx_buffers[cpu_index] + + vum->cpus[cpu_index].rx_buffers + curr_len, - 2 * VLIB_FRAME_SIZE - curr_len, + VHOST_USER_RX_BUFFERS_N - curr_len, VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX); - if (PREDICT_FALSE (n_left > _vec_len (vum->rx_buffers[cpu_index]))) - flush = n_left - _vec_len (vum->rx_buffers[cpu_index]); - } - - if (PREDICT_FALSE (flush)) - { - //Remove some input buffers - drops += flush; - n_left -= flush; - vlib_error_count (vm, vhost_user_input_node.index, - VHOST_USER_INPUT_FUNC_ERROR_NO_BUFFER, flush); - while (flush) + if (PREDICT_FALSE + (vum->cpus[cpu_index].rx_buffers_len < + VHOST_USER_RX_BUFFER_STARVATION)) { - u16 desc_chain_head = - txvq->avail->ring[txvq->last_avail_idx & qsz_mask]; - txvq->last_avail_idx++; - txvq->used->ring[txvq->last_used_idx & qsz_mask].id = - desc_chain_head; - txvq->used->ring[txvq->last_used_idx & qsz_mask].len = 0; - vhost_user_log_dirty_ring (vui, txvq, - ring[txvq->last_used_idx & qsz_mask]); - txvq->last_used_idx++; - flush--; + /* In case of buffer starvation, discard some packets from the queue + * and log the event. + * We keep doing best effort for the remaining packets. */ + u32 flush = (n_left + 1 > vum->cpus[cpu_index].rx_buffers_len) ? + n_left + 1 - vum->cpus[cpu_index].rx_buffers_len : 1; + flush = vhost_user_rx_discard_packet (vm, vui, txvq, flush); + + n_left -= flush; + vlib_increment_simple_counter (vnet_main. + interface_main.sw_if_counters + + VNET_INTERFACE_COUNTER_DROP, + os_get_cpu_number (), + vui->sw_if_index, flush); + + vlib_error_count (vm, vhost_user_input_node.index, + VHOST_USER_INPUT_FUNC_ERROR_NO_BUFFER, flush); } } - rx_len = vec_len (vum->rx_buffers[cpu_index]); //vector might be null while (n_left > 0) { vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next); @@ -1454,32 +1575,48 @@ vhost_user_if_input (vlib_main_t * vm, while (n_left > 0 && n_left_to_next > 0) { vlib_buffer_t *b_head, *b_current; - u32 bi_head, bi_current; - u16 desc_chain_head, desc_current; - u8 error = VHOST_USER_INPUT_FUNC_ERROR_NO_ERROR; + u32 bi_current; + u16 desc_current; + u32 desc_data_offset; + vring_desc_t *desc_table = txvq->desc; - if (PREDICT_TRUE (n_left > 1)) + if (PREDICT_FALSE (vum->cpus[cpu_index].rx_buffers_len <= 1)) { - u32 next_desc = - txvq->avail->ring[(txvq->last_avail_idx + 1) & qsz_mask]; - void *buffer_addr = - map_guest_mem (vui, txvq->desc[next_desc].addr, - &map_guest_hint_desc); - if (PREDICT_TRUE (buffer_addr != 0)) - CLIB_PREFETCH (buffer_addr, 64, STORE); - - u32 bi = vum->rx_buffers[cpu_index][rx_len - 2]; - vlib_prefetch_buffer_with_index (vm, bi, STORE); - CLIB_PREFETCH (vlib_get_buffer (vm, bi)->data, 128, STORE); + /* Not enough rx_buffers + * Note: We yeld on 1 so we don't need to do an additional + * check for the next buffer prefetch. + */ + n_left = 0; + break; } - desc_chain_head = desc_current = - txvq->avail->ring[txvq->last_avail_idx & qsz_mask]; - bi_head = bi_current = vum->rx_buffers[cpu_index][--rx_len]; - b_head = b_current = vlib_get_buffer (vm, bi_head); - vlib_buffer_chain_init (b_head); + desc_current = txvq->avail->ring[txvq->last_avail_idx & qsz_mask]; + vum->cpus[cpu_index].rx_buffers_len--; + bi_current = (vum->cpus[cpu_index].rx_buffers) + [vum->cpus[cpu_index].rx_buffers_len]; + b_head = b_current = vlib_get_buffer (vm, bi_current); + to_next[0] = bi_current; //We do that now so we can forget about bi_current + to_next++; + n_left_to_next--; + + vlib_prefetch_buffer_with_index (vm, + (vum->cpus[cpu_index].rx_buffers) + [vum->cpus[cpu_index]. + rx_buffers_len - 1], LOAD); + + /* Just preset the used descriptor id and length for later */ + txvq->used->ring[txvq->last_used_idx & qsz_mask].id = desc_current; + txvq->used->ring[txvq->last_used_idx & qsz_mask].len = 0; + vhost_user_log_dirty_ring (vui, txvq, + ring[txvq->last_used_idx & qsz_mask]); + + /* The buffer should already be initialized */ + b_head->total_length_not_including_first_buffer = 0; + b_head->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID; + if (PREDICT_FALSE (n_trace)) { + //TODO: next_index is not exactly known at that point vlib_trace_buffer (vm, node, next_index, b_head, /* follow_chain */ 0); vhost_trace_t *t0 = @@ -1489,148 +1626,173 @@ vhost_user_if_input (vlib_main_t * vm, vlib_set_trace_count (vm, node, n_trace); } - uword offset; - if (PREDICT_TRUE (vui->is_any_layout) || - (!(txvq->desc[desc_current].flags & VIRTQ_DESC_F_NEXT) && - !(txvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT))) - { - /* ANYLAYOUT or single buffer */ - offset = vui->virtio_net_hdr_sz; - } - else - { - /* CSR case without ANYLAYOUT, skip 1st buffer */ - offset = txvq->desc[desc_current].len; - } - - vring_desc_t *desc_table = txvq->desc; - u32 desc_index = desc_current; - map_guest_hint_p = &map_guest_hint_desc; - + /* This depends on the setup but is very consistent + * So I think the CPU branch predictor will make a pretty good job + * at optimizing the decision. */ if (txvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT) { desc_table = map_guest_mem (vui, txvq->desc[desc_current].addr, - &map_guest_hint_desc); - desc_index = 0; - map_guest_hint_p = &map_guest_hint_indirect; + &map_hint); + desc_current = 0; if (PREDICT_FALSE (desc_table == 0)) { - error = VHOST_USER_INPUT_FUNC_ERROR_MMAP_FAIL; + //FIXME: Handle error by shutdown the queue goto out; } } - while (1) + if (PREDICT_TRUE (vui->is_any_layout) || + (!(desc_table[desc_current].flags & VIRTQ_DESC_F_NEXT))) { - void *buffer_addr = - map_guest_mem (vui, desc_table[desc_index].addr, - map_guest_hint_p); - if (PREDICT_FALSE (buffer_addr == 0)) - { - error = VHOST_USER_INPUT_FUNC_ERROR_MMAP_FAIL; - goto out; - } + /* ANYLAYOUT or single buffer */ + desc_data_offset = vui->virtio_net_hdr_sz; + } + else + { + /* CSR case without ANYLAYOUT, skip 1st buffer */ + desc_data_offset = desc_table[desc_current].len; + } - if (PREDICT_TRUE - (desc_table[desc_index].flags & VIRTQ_DESC_F_NEXT)) + while (1) + { + /* Get more input if necessary. Or end of packet. */ + if (desc_data_offset == desc_table[desc_current].len) { - CLIB_PREFETCH (&desc_table[desc_table[desc_index].next], - sizeof (vring_desc_t), STORE); + if (PREDICT_FALSE (desc_table[desc_current].flags & + VIRTQ_DESC_F_NEXT)) + { + desc_current = desc_table[desc_current].next; + desc_data_offset = 0; + } + else + { + goto out; + } } - if (desc_table[desc_index].len > offset) + /* Get more output if necessary. Or end of packet. */ + if (PREDICT_FALSE + (b_current->current_length == VLIB_BUFFER_DATA_SIZE)) { - u16 len = desc_table[desc_index].len - offset; - u16 copied = vlib_buffer_chain_append_data_with_alloc (vm, - VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX, - b_head, - &b_current, - buffer_addr - + - offset, - len); - if (copied != len) + if (PREDICT_FALSE + (vum->cpus[cpu_index].rx_buffers_len == 0)) { - error = VHOST_USER_INPUT_FUNC_ERROR_NO_BUFFER; - break; + /* + * Checking if there are some left buffers. + * If not, just rewind the used buffers and stop. + * Note: Scheduled copies are not cancelled. This is + * not an issue as they would still be valid. Useless, + * but valid. + */ + vhost_user_input_rewind_buffers (vm, + &vum->cpus[cpu_index], + b_head); + n_left = 0; + goto stop; } + + /* Get next output */ + vum->cpus[cpu_index].rx_buffers_len--; + u32 bi_next = + (vum->cpus[cpu_index].rx_buffers)[vum->cpus + [cpu_index].rx_buffers_len]; + b_current->next_buffer = bi_next; + b_current->flags |= VLIB_BUFFER_NEXT_PRESENT; + bi_current = bi_next; + b_current = vlib_get_buffer (vm, bi_current); } - offset = 0; - /* if next flag is set, take next desc in the chain */ - if ((desc_table[desc_index].flags & VIRTQ_DESC_F_NEXT)) - desc_index = desc_table[desc_index].next; - else - goto out; + /* Prepare a copy order executed later for the data */ + vhost_copy_t *cpy = &vum->cpus[cpu_index].copy[copy_len]; + copy_len++; + u32 desc_data_l = + desc_table[desc_current].len - desc_data_offset; + cpy->len = VLIB_BUFFER_DATA_SIZE - b_current->current_length; + cpy->len = (cpy->len > desc_data_l) ? desc_data_l : cpy->len; + cpy->dst = (uword) vlib_buffer_get_current (b_current); + cpy->src = desc_table[desc_current].addr + desc_data_offset; + + desc_data_offset += cpy->len; + + b_current->current_length += cpy->len; + b_head->total_length_not_including_first_buffer += cpy->len; } + out: + CLIB_PREFETCH (&n_left, sizeof (n_left), LOAD); + + n_rx_bytes += b_head->total_length_not_including_first_buffer; + n_rx_packets++; + + b_head->total_length_not_including_first_buffer -= + b_head->current_length; /* consume the descriptor and return it as used */ txvq->last_avail_idx++; - txvq->used->ring[txvq->last_used_idx & qsz_mask].id = - desc_chain_head; - txvq->used->ring[txvq->last_used_idx & qsz_mask].len = 0; - vhost_user_log_dirty_ring (vui, txvq, - ring[txvq->last_used_idx & qsz_mask]); txvq->last_used_idx++; - //It is important to free RX as fast as possible such that the TX - //process does not drop packets - if ((txvq->last_used_idx & 0x3f) == 0) // Every 64 packets - txvq->used->idx = txvq->last_used_idx; - - if (PREDICT_FALSE (b_head->current_length < 14 && - error == VHOST_USER_INPUT_FUNC_ERROR_NO_ERROR)) - error = VHOST_USER_INPUT_FUNC_ERROR_UNDERSIZED_FRAME; - VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b_head); vnet_buffer (b_head)->sw_if_index[VLIB_RX] = vui->sw_if_index; vnet_buffer (b_head)->sw_if_index[VLIB_TX] = (u32) ~ 0; - b_head->error = node->errors[error]; + b_head->error = 0; - if (PREDICT_FALSE (error)) - { - drops++; - next0 = VNET_DEVICE_INPUT_NEXT_DROP; - } - else - { - n_rx_bytes += - b_head->current_length + - b_head->total_length_not_including_first_buffer; - n_rx_packets++; - next0 = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT; - } + { + u32 next0 = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT; - to_next[0] = bi_head; - to_next++; - n_left_to_next--; + /* redirect if feature path enabled */ + vnet_feature_start_device_input_x1 (vui->sw_if_index, &next0, + b_head, 0); - /* redirect if feature path enabled */ - vnet_feature_start_device_input_x1 (vui->sw_if_index, &next0, - b_head, 0); + u32 bi = to_next[-1]; //Cannot use to_next[-1] in the macro + vlib_validate_buffer_enqueue_x1 (vm, node, next_index, + to_next, n_left_to_next, + bi, next0); + } - vlib_validate_buffer_enqueue_x1 (vm, node, next_index, - to_next, n_left_to_next, - bi_head, next0); n_left--; - if (PREDICT_FALSE (!n_left)) + + /* + * Although separating memory copies from virtio ring parsing + * is beneficial, we can offer to perform the copies from time + * to time in order to free some space in the ring. + */ + if (PREDICT_FALSE (copy_len >= VHOST_USER_RX_COPY_THRESHOLD)) { - // I NEED SOME MORE ! - u32 remain = (u16) (txvq->avail->idx - txvq->last_avail_idx); - remain = (remain > VLIB_FRAME_SIZE - n_rx_packets) ? - VLIB_FRAME_SIZE - n_rx_packets : remain; - remain = (remain > rx_len) ? rx_len : remain; - n_left = remain; + if (PREDICT_FALSE + (vhost_user_input_copy (vui, vum->cpus[cpu_index].copy, + copy_len, &map_hint))) + { + clib_warning + ("Memory mapping error on interface hw_if_index=%d " + "(Shutting down - Switch interface down and up to restart)", + vui->hw_if_index); + vui->admin_up = 0; + copy_len = 0; + break; + } + copy_len = 0; + + /* give buffers back to driver */ + CLIB_MEMORY_BARRIER (); + txvq->used->idx = txvq->last_used_idx; + vhost_user_log_dirty_ring (vui, txvq, idx); } } - + stop: vlib_put_next_frame (vm, node, next_index, n_left_to_next); } - if (PREDICT_TRUE (vum->rx_buffers[cpu_index] != 0)) - _vec_len (vum->rx_buffers[cpu_index]) = rx_len; + /* Do the memory copies */ + if (PREDICT_FALSE + (vhost_user_input_copy (vui, vum->cpus[cpu_index].copy, + copy_len, &map_hint))) + { + clib_warning ("Memory mapping error on interface hw_if_index=%d " + "(Shutting down - Switch interface down and up to restart)", + vui->hw_if_index); + vui->admin_up = 0; + } /* give buffers back to driver */ CLIB_MEMORY_BARRIER (); @@ -1646,14 +1808,6 @@ vhost_user_if_input (vlib_main_t * vm, vhost_user_send_call (vm, txvq); } - if (PREDICT_FALSE (drops)) - { - vlib_increment_simple_counter - (vnet_main.interface_main.sw_if_counters - + VNET_INTERFACE_COUNTER_DROP, os_get_cpu_number (), - vui->sw_if_index, drops); - } - /* increase rx counters */ vlib_increment_combined_counter (vnet_main.interface_main.combined_sw_if_counters @@ -1680,8 +1834,6 @@ vhost_user_input (vlib_main_t * vm, n_rx_packets += vhost_user_if_input (vm, vum, vui, vhiq->qid, node); } - //TODO: One call might return more than 256 packets here. - //But this is supposed to be the vector size. return n_rx_packets; } @@ -1726,7 +1878,7 @@ vhost_user_tx_trace (vhost_trace_t * t, if (rxvq->desc[desc_current].flags & VIRTQ_DESC_F_INDIRECT) { t->virtio_ring_flags |= 1 << VIRTIO_TRACE_F_INDIRECT; - //Header is the first here + /* Header is the first here */ hdr_desc = map_guest_mem (vui, rxvq->desc[desc_current].addr, &hint); } if (rxvq->desc[desc_current].flags & VIRTQ_DESC_F_NEXT) @@ -1742,290 +1894,348 @@ vhost_user_tx_trace (vhost_trace_t * t, t->first_desc_len = hdr_desc ? hdr_desc->len : 0; } +static_always_inline u32 +vhost_user_tx_copy (vhost_user_intf_t * vui, vhost_copy_t * cpy, + u16 copy_len, u32 * map_hint) +{ + void *dst0, *dst1, *dst2, *dst3; + if (PREDICT_TRUE (copy_len >= 4)) + { + if (PREDICT_FALSE (!(dst2 = map_guest_mem (vui, cpy[0].dst, map_hint)))) + return 1; + if (PREDICT_FALSE (!(dst3 = map_guest_mem (vui, cpy[1].dst, map_hint)))) + return 1; + while (PREDICT_TRUE (copy_len >= 4)) + { + dst0 = dst2; + dst1 = dst3; + + if (PREDICT_FALSE + (!(dst2 = map_guest_mem (vui, cpy[2].dst, map_hint)))) + return 1; + if (PREDICT_FALSE + (!(dst3 = map_guest_mem (vui, cpy[3].dst, map_hint)))) + return 1; + + CLIB_PREFETCH ((void *) cpy[2].src, 64, LOAD); + CLIB_PREFETCH ((void *) cpy[3].src, 64, LOAD); + + clib_memcpy (dst0, (void *) cpy[0].src, cpy[0].len); + clib_memcpy (dst1, (void *) cpy[1].src, cpy[1].len); + + vhost_user_log_dirty_pages_2 (vui, cpy[0].dst, cpy[0].len, 1); + vhost_user_log_dirty_pages_2 (vui, cpy[1].dst, cpy[1].len, 1); + copy_len -= 2; + cpy += 2; + } + } + while (copy_len) + { + if (PREDICT_FALSE (!(dst0 = map_guest_mem (vui, cpy->dst, map_hint)))) + return 1; + clib_memcpy (dst0, (void *) cpy->src, cpy->len); + vhost_user_log_dirty_pages_2 (vui, cpy->dst, cpy->len, 1); + copy_len -= 1; + cpy += 1; + } + return 0; +} + + static uword vhost_user_tx (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * frame) { u32 *buffers = vlib_frame_args (frame); - u32 n_left = 0; + u32 n_left = frame->n_vectors; vhost_user_main_t *vum = &vhost_user_main; - uword n_packets = 0; vnet_interface_output_runtime_t *rd = (void *) node->runtime_data; vhost_user_intf_t *vui = pool_elt_at_index (vum->vhost_user_interfaces, rd->dev_instance); u32 qid = ~0; vhost_user_vring_t *rxvq; u16 qsz_mask; - u8 error = VHOST_USER_TX_FUNC_ERROR_NONE; + u8 error; u32 cpu_index = os_get_cpu_number (); - n_left = n_packets = frame->n_vectors; - u32 map_guest_hint_desc = 0; - u32 map_guest_hint_indirect = 0; - u32 *map_guest_hint_p = &map_guest_hint_desc; - vhost_trace_t *current_trace = 0; - int n_retry; + u32 map_hint = 0; + u8 retry = 8; + u16 copy_len; + u16 tx_headers_len; + + if (PREDICT_FALSE (!vui->admin_up)) + { + error = VHOST_USER_TX_FUNC_ERROR_DOWN; + goto done3; + } - if (PREDICT_FALSE (!vui->is_up || !vui->admin_up)) + if (PREDICT_FALSE (!vui->is_up)) { error = VHOST_USER_TX_FUNC_ERROR_NOT_READY; goto done3; } qid = - VHOST_VRING_IDX_RX (*vec_elt_at_index (vui->per_cpu_tx_qid, cpu_index)); + VHOST_VRING_IDX_RX (*vec_elt_at_index + (vui->per_cpu_tx_qid, os_get_cpu_number ())); rxvq = &vui->vrings[qid]; if (PREDICT_FALSE (vui->use_tx_spinlock)) vhost_user_vring_lock (vui, qid); - if (PREDICT_FALSE ((rxvq->avail->idx == rxvq->last_avail_idx))) - { - error = VHOST_USER_TX_FUNC_ERROR_PKT_DROP_NOBUF; - goto done2; - } - qsz_mask = rxvq->qsz - 1; /* qsz is always power of 2 */ - n_retry = 8; - while (n_left > 0 && n_retry--) +retry: + error = VHOST_USER_TX_FUNC_ERROR_NONE; + tx_headers_len = 0; + copy_len = 0; + while (n_left > 0) { + vlib_buffer_t *b0, *current_b0; + u16 desc_head, desc_index, desc_len; + vring_desc_t *desc_table; + uword buffer_map_addr; + u32 buffer_len; + u16 bytes_left; - while (n_left > 0) + if (PREDICT_TRUE (n_left > 1)) + vlib_prefetch_buffer_with_index (vm, buffers[1], LOAD); + + b0 = vlib_get_buffer (vm, buffers[0]); + + if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED)) { - vlib_buffer_t *b0, *current_b0; - u16 desc_head, desc_index, desc_len; - vring_desc_t *desc_table; - void *buffer_addr; - u32 buffer_len; + vum->cpus[cpu_index].current_trace = + vlib_add_trace (vm, node, b0, + sizeof (*vum->cpus[cpu_index].current_trace)); + vhost_user_tx_trace (vum->cpus[cpu_index].current_trace, + vui, qid / 2, b0, rxvq); + } - b0 = vlib_get_buffer (vm, buffers[0]); + if (PREDICT_FALSE (rxvq->last_avail_idx == rxvq->avail->idx)) + { + error = VHOST_USER_TX_FUNC_ERROR_PKT_DROP_NOBUF; + goto done; + } - if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED)) - { - current_trace = vlib_add_trace (vm, node, b0, - sizeof (*current_trace)); - vhost_user_tx_trace (current_trace, vui, qid / 2, b0, rxvq); - } + desc_table = rxvq->desc; + desc_head = desc_index = + rxvq->avail->ring[rxvq->last_avail_idx & qsz_mask]; - if (PREDICT_FALSE (rxvq->last_avail_idx == rxvq->avail->idx)) + /* Go deeper in case of indirect descriptor + * I don't know of any driver providing indirect for RX. */ + if (PREDICT_FALSE (rxvq->desc[desc_head].flags & VIRTQ_DESC_F_INDIRECT)) + { + if (PREDICT_FALSE + (rxvq->desc[desc_head].len < sizeof (vring_desc_t))) { - error = VHOST_USER_TX_FUNC_ERROR_PKT_DROP_NOBUF; + error = VHOST_USER_TX_FUNC_ERROR_INDIRECT_OVERFLOW; goto done; } - - desc_table = rxvq->desc; - map_guest_hint_p = &map_guest_hint_desc; - desc_head = desc_index = - rxvq->avail->ring[rxvq->last_avail_idx & qsz_mask]; - if (rxvq->desc[desc_head].flags & VIRTQ_DESC_F_INDIRECT) - { - if (PREDICT_FALSE - (rxvq->desc[desc_head].len < sizeof (vring_desc_t))) - { - error = VHOST_USER_TX_FUNC_ERROR_INDIRECT_OVERFLOW; - goto done; - } - if (PREDICT_FALSE - (!(desc_table = - map_guest_mem (vui, rxvq->desc[desc_index].addr, - &map_guest_hint_desc)))) - { - error = VHOST_USER_TX_FUNC_ERROR_MMAP_FAIL; - goto done; - } - desc_index = 0; - map_guest_hint_p = &map_guest_hint_indirect; - } - - desc_len = vui->virtio_net_hdr_sz; - if (PREDICT_FALSE - (!(buffer_addr = - map_guest_mem (vui, desc_table[desc_index].addr, - map_guest_hint_p)))) + (!(desc_table = + map_guest_mem (vui, rxvq->desc[desc_index].addr, + &map_hint)))) { error = VHOST_USER_TX_FUNC_ERROR_MMAP_FAIL; goto done; } - buffer_len = desc_table[desc_index].len; - - CLIB_PREFETCH (buffer_addr, CLIB_CACHE_LINE_BYTES, STORE); + desc_index = 0; + } - virtio_net_hdr_mrg_rxbuf_t *hdr = - (virtio_net_hdr_mrg_rxbuf_t *) buffer_addr; - hdr->hdr.flags = 0; - hdr->hdr.gso_type = 0; - if (vui->virtio_net_hdr_sz == 12) - hdr->num_buffers = 1; + desc_len = vui->virtio_net_hdr_sz; + buffer_map_addr = desc_table[desc_index].addr; + buffer_len = desc_table[desc_index].len; - vhost_user_log_dirty_pages (vui, desc_table[desc_index].addr, - vui->virtio_net_hdr_sz); + { + // Get a header from the header array + virtio_net_hdr_mrg_rxbuf_t *hdr = + &vum->cpus[cpu_index].tx_headers[tx_headers_len]; + tx_headers_len++; + hdr->hdr.flags = 0; + hdr->hdr.gso_type = 0; + hdr->num_buffers = 1; //This is local, no need to check + + // Prepare a copy order executed later for the header + vhost_copy_t *cpy = &vum->cpus[cpu_index].copy[copy_len]; + copy_len++; + cpy->len = vui->virtio_net_hdr_sz; + cpy->dst = buffer_map_addr; + cpy->src = (uword) hdr; + } - u16 bytes_left = b0->current_length; - buffer_addr += vui->virtio_net_hdr_sz; - buffer_len -= vui->virtio_net_hdr_sz; - current_b0 = b0; - while (1) - { - if (!bytes_left) - { //Get new input - if (current_b0->flags & VLIB_BUFFER_NEXT_PRESENT) - { - current_b0 = - vlib_get_buffer (vm, current_b0->next_buffer); - bytes_left = current_b0->current_length; - } - else - { - //End of packet - break; - } + buffer_map_addr += vui->virtio_net_hdr_sz; + buffer_len -= vui->virtio_net_hdr_sz; + bytes_left = b0->current_length; + current_b0 = b0; + while (1) + { + if (buffer_len == 0) + { //Get new output + if (desc_table[desc_index].flags & VIRTQ_DESC_F_NEXT) + { + //Next one is chained + desc_index = desc_table[desc_index].next; + buffer_map_addr = desc_table[desc_index].addr; + buffer_len = desc_table[desc_index].len; } - - if (buffer_len == 0) - { //Get new output - if (desc_table[desc_index].flags & VIRTQ_DESC_F_NEXT) + else if (vui->virtio_net_hdr_sz == 12) //MRG is available + { + virtio_net_hdr_mrg_rxbuf_t *hdr = + &vum->cpus[cpu_index].tx_headers[tx_headers_len - 1]; + + //Move from available to used buffer + rxvq->used->ring[rxvq->last_used_idx & qsz_mask].id = + desc_head; + rxvq->used->ring[rxvq->last_used_idx & qsz_mask].len = + desc_len; + vhost_user_log_dirty_ring (vui, rxvq, + ring[rxvq->last_used_idx & + qsz_mask]); + + rxvq->last_avail_idx++; + rxvq->last_used_idx++; + hdr->num_buffers++; + desc_len = 0; + + if (PREDICT_FALSE + (rxvq->last_avail_idx == rxvq->avail->idx)) { - //Next one is chained - desc_index = desc_table[desc_index].next; - if (PREDICT_FALSE - (!(buffer_addr = - map_guest_mem (vui, desc_table[desc_index].addr, - map_guest_hint_p)))) - { - rxvq->last_used_idx -= hdr->num_buffers - 1; - rxvq->last_avail_idx -= hdr->num_buffers - 1; - error = VHOST_USER_TX_FUNC_ERROR_MMAP_FAIL; - goto done; - } - buffer_len = desc_table[desc_index].len; + //Dequeue queued descriptors for this packet + rxvq->last_used_idx -= hdr->num_buffers - 1; + rxvq->last_avail_idx -= hdr->num_buffers - 1; + error = VHOST_USER_TX_FUNC_ERROR_PKT_DROP_NOBUF; + goto done; } - else if (vui->virtio_net_hdr_sz == 12) //MRG is available - { - //Move from available to used buffer - rxvq->used->ring[rxvq->last_used_idx & qsz_mask].id = - desc_head; - rxvq->used->ring[rxvq->last_used_idx & qsz_mask].len = - desc_len; - vhost_user_log_dirty_ring (vui, rxvq, - ring[rxvq->last_used_idx & - qsz_mask]); - rxvq->last_avail_idx++; - rxvq->last_used_idx++; - hdr->num_buffers++; + desc_table = rxvq->desc; + desc_head = desc_index = + rxvq->avail->ring[rxvq->last_avail_idx & qsz_mask]; + if (PREDICT_FALSE + (rxvq->desc[desc_head].flags & VIRTQ_DESC_F_INDIRECT)) + { + //It is seriously unlikely that a driver will put indirect descriptor + //after non-indirect descriptor. if (PREDICT_FALSE - (rxvq->last_avail_idx == rxvq->avail->idx)) + (rxvq->desc[desc_head].len < sizeof (vring_desc_t))) { - //Dequeue queued descriptors for this packet - rxvq->last_used_idx -= hdr->num_buffers - 1; - rxvq->last_avail_idx -= hdr->num_buffers - 1; - error = VHOST_USER_TX_FUNC_ERROR_PKT_DROP_NOBUF; + error = VHOST_USER_TX_FUNC_ERROR_INDIRECT_OVERFLOW; goto done; } - - desc_table = rxvq->desc; - map_guest_hint_p = &map_guest_hint_desc; - desc_head = desc_index = - rxvq->avail->ring[rxvq->last_avail_idx & qsz_mask]; - if (PREDICT_FALSE - (rxvq-> - desc[desc_head].flags & VIRTQ_DESC_F_INDIRECT)) - { - //It is seriously unlikely that a driver will put indirect descriptor - //after non-indirect descriptor. - if (PREDICT_FALSE - (rxvq->desc[desc_head].len < - sizeof (vring_desc_t))) - { - error = - VHOST_USER_TX_FUNC_ERROR_INDIRECT_OVERFLOW; - goto done; - } - if (PREDICT_FALSE - (!(desc_table = - map_guest_mem (vui, - rxvq->desc[desc_index].addr, - &map_guest_hint_desc)))) - { - error = VHOST_USER_TX_FUNC_ERROR_MMAP_FAIL; - goto done; - } - desc_index = 0; - map_guest_hint_p = &map_guest_hint_indirect; - } - if (PREDICT_FALSE - (!(buffer_addr = - map_guest_mem (vui, desc_table[desc_index].addr, - map_guest_hint_p)))) + (!(desc_table = + map_guest_mem (vui, + rxvq->desc[desc_index].addr, + &map_hint)))) { error = VHOST_USER_TX_FUNC_ERROR_MMAP_FAIL; goto done; } - buffer_len = desc_table[desc_index].len; - CLIB_PREFETCH (buffer_addr, CLIB_CACHE_LINE_BYTES, - STORE); - } - else - { - error = VHOST_USER_TX_FUNC_ERROR_PKT_DROP_NOMRG; - goto done; + desc_index = 0; } + buffer_map_addr = desc_table[desc_index].addr; + buffer_len = desc_table[desc_index].len; + } + else + { + error = VHOST_USER_TX_FUNC_ERROR_PKT_DROP_NOMRG; + goto done; } - - u16 bytes_to_copy = bytes_left; - bytes_to_copy = - (bytes_to_copy > buffer_len) ? buffer_len : bytes_to_copy; - clib_memcpy (buffer_addr, - vlib_buffer_get_current (current_b0) + - current_b0->current_length - bytes_left, - bytes_to_copy); - - vhost_user_log_dirty_pages (vui, - desc_table[desc_index].addr + - desc_table[desc_index].len - - bytes_left - bytes_to_copy, - bytes_to_copy); - - CLIB_PREFETCH (rxvq, sizeof (*rxvq), STORE); - bytes_left -= bytes_to_copy; - buffer_len -= bytes_to_copy; - buffer_addr += bytes_to_copy; - desc_len += bytes_to_copy; } - //Move from available to used ring - rxvq->used->ring[rxvq->last_used_idx & qsz_mask].id = desc_head; - rxvq->used->ring[rxvq->last_used_idx & qsz_mask].len = desc_len; - vhost_user_log_dirty_ring (vui, rxvq, - ring[rxvq->last_used_idx & qsz_mask]); + { + vhost_copy_t *cpy = &vum->cpus[cpu_index].copy[copy_len]; + copy_len++; + cpy->len = bytes_left; + cpy->len = (cpy->len > buffer_len) ? buffer_len : cpy->len; + cpy->dst = buffer_map_addr; + cpy->src = (uword) vlib_buffer_get_current (current_b0) + + current_b0->current_length - bytes_left; + + bytes_left -= cpy->len; + buffer_len -= cpy->len; + buffer_map_addr += cpy->len; + desc_len += cpy->len; + + CLIB_PREFETCH (&rxvq->desc, sizeof (&rxvq->desc), LOAD); + } - rxvq->last_avail_idx++; - rxvq->last_used_idx++; + // Check if vlib buffer has more data. If not, get more or break. + if (PREDICT_TRUE (!bytes_left)) + { + if (PREDICT_FALSE + (current_b0->flags & VLIB_BUFFER_NEXT_PRESENT)) + { + current_b0 = vlib_get_buffer (vm, current_b0->next_buffer); + bytes_left = current_b0->current_length; + } + else + { + //End of packet + break; + } + } + } - if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED)) - current_trace->hdr = *hdr; + //Move from available to used ring + rxvq->used->ring[rxvq->last_used_idx & qsz_mask].id = desc_head; + rxvq->used->ring[rxvq->last_used_idx & qsz_mask].len = desc_len; + vhost_user_log_dirty_ring (vui, rxvq, + ring[rxvq->last_used_idx & qsz_mask]); + rxvq->last_avail_idx++; + rxvq->last_used_idx++; - buffers++; - n_left--; //At the end for error counting when 'goto done' is invoked + if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED)) + { + vum->cpus[cpu_index].current_trace->hdr = + vum->cpus[cpu_index].tx_headers[tx_headers_len - 1]; } - done: - CLIB_MEMORY_BARRIER (); - rxvq->used->idx = rxvq->last_used_idx; - vhost_user_log_dirty_ring (vui, rxvq, idx); + n_left--; //At the end for error counting when 'goto done' is invoked + buffers++; + } + +done: + //Do the memory copies + if (PREDICT_FALSE + (vhost_user_tx_copy (vui, vum->cpus[cpu_index].copy, + copy_len, &map_hint))) + { + clib_warning ("Memory mapping error on interface hw_if_index=%d " + "(Shutting down - Switch interface down and up to restart)", + vui->hw_if_index); + vui->admin_up = 0; + } + + CLIB_MEMORY_BARRIER (); + rxvq->used->idx = rxvq->last_used_idx; + vhost_user_log_dirty_ring (vui, rxvq, idx); + + /* + * When n_left is set, error is always set to something too. + * In case error is due to lack of remaining buffers, we go back up and + * retry. + * The idea is that it is better to waste some time on packets + * that have been processed already than dropping them and get + * more fresh packets with a good likelyhood that they will be dropped too. + * This technique also gives more time to VM driver to pick-up packets. + * In case the traffic flows from physical to virtual interfaces, this + * technique will end-up leveraging the physical NIC buffer in order to + * absorb the VM's CPU jitter. + */ + if (n_left && (error == VHOST_USER_TX_FUNC_ERROR_PKT_DROP_NOBUF) && retry) + { + retry--; + goto retry; } /* interrupt (call) handling */ if ((rxvq->callfd_idx != ~0) && !(rxvq->avail->flags & 1)) { - rxvq->n_since_last_int += n_packets - n_left; + rxvq->n_since_last_int += frame->n_vectors - n_left; if (rxvq->n_since_last_int > vum->coalesce_frames) vhost_user_send_call (vm, rxvq); } -done2: vhost_user_vring_unlock (vui, qid); done3: