Based on the comments in the struct, udp_encap_t_ is meant to span 2
cachelines. Due to the 64 bit alignment of dpo_id_t, the struct spanned
3 cachelines. This caused fetching ue_ip_proto to trigger an additional
cache miss. This patch rearranges the ordering of the struct fields
so that udp_encap_t_ only spans 2 cachelines as intended.
before:
(gdb) print (int)&((struct udp_encap_t_*)0)->cacheline1
$8 = 128
after:
(gdb) print (int)&((struct udp_encap_t_*)0)->cacheline1
$1 = 64
Type: fix
Signed-off-by: Vadym Martsynovskyy <vmartsyn@fb.com>
Change-Id: I066c08654d4a8ef3e2d3954e957d4c5d382b209f
(cherry picked from commit
42386fc974148f812ef3eb73ff09a603caa23565)
} __attribute__ ((packed)) ue_hdrs;
/**
- * Flags controlling fixup behaviour
+ * The DPO used to forward to the next node in the VLIB graph
*/
- udp_encap_fixup_flags_t ue_flags;
+ dpo_id_t ue_dpo;
/**
- * The DPO used to forward to the next node in the VLIB graph
+ * Flags controlling fixup behaviour
*/
- dpo_id_t ue_dpo;
+ udp_encap_fixup_flags_t ue_flags;
/**
* the protocol of the IP header imposed