From 0be1b764a3111a4107f81e42fba9cf99bf1c9baf Mon Sep 17 00:00:00 2001 From: Damjan Marion Date: Fri, 4 Sep 2020 12:34:58 +0200 Subject: [PATCH] buffers: improve cache occupancy Adjust buffer allocation so it always have odd number of cache lines. That should result in better distribution of cachelines among cache sets. Type: improvement Change-Id: I0d39d4cf01cff36ad6f70a700730823a96448c22 Signed-off-by: Damjan Marion --- src/vlib/buffer.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/src/vlib/buffer.c b/src/vlib/buffer.c index a645438640a..17e7d24cb27 100644 --- a/src/vlib/buffer.c +++ b/src/vlib/buffer.c @@ -507,8 +507,14 @@ vlib_buffer_chain_append_data_with_alloc (vlib_main_t * vm, static uword vlib_buffer_alloc_size (uword ext_hdr_size, uword data_size) { - return CLIB_CACHE_LINE_ROUND (ext_hdr_size + sizeof (vlib_buffer_t) + - data_size); + uword alloc_size = ext_hdr_size + sizeof (vlib_buffer_t) + data_size; + alloc_size = CLIB_CACHE_LINE_ROUND (alloc_size); + + /* in case when we have even number of cachelines, we add one more for + * better cache occupancy */ + alloc_size |= CLIB_CACHE_LINE_BYTES; + + return alloc_size; } u8 -- 2.16.6