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-rw-r--r--src/vnet/adj/rewrite.h16
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)) \