diff options
| -rw-r--r-- | src/vnet/adj/rewrite.h | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/src/vnet/adj/rewrite.h b/src/vnet/adj/rewrite.h index 58d47e0c737..32781134ecc 100644 --- a/src/vnet/adj/rewrite.h +++ b/src/vnet/adj/rewrite.h @@ -189,7 +189,13 @@ _vnet_rewrite_one_header (vnet_rewrite_header_t * h0, clib_memcpy (d, s, sizeof (eh_copy_t)); return; } - + /* + * Stop now if the data_bytes field is zero, to avoid the cache + * miss consequences of spraying [functionally harmless] junk into + * un-prefetched rewrite space. + */ + if (PREDICT_FALSE (h0->data_bytes == 0)) + return; #define _(i) \ do { \ @@ -244,6 +250,14 @@ _vnet_rewrite_two_headers (vnet_rewrite_header_t * h0, return; } + /* + * Stop now if both rewrite data_bytes fields are zero, to avoid the cache + * miss consequences of spraying [functionally harmless] junk into + * un-prefetched rewrite space. + */ + if (PREDICT_FALSE (h0->data_bytes + h1->data_bytes == 0)) + return; + #define _(i) \ do { \ if (most_likely_size > ((i)-1)*sizeof (vnet_rewrite_data_t)) \ |