path: root/examples/l3fwd
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authorGuduri Prathyusha <>2017-11-03 16:13:51 +0530
committerFerruh Yigit <>2017-11-07 09:04:42 +0000
commit01ac23460c36927e019473e71b582223ad6b79c5 (patch)
tree4b93ab5b92152af7ca14aa3b9769ea977688a114 /examples/l3fwd
parent3a4475e51d13ec3328b291061c38b7c5643a86ee (diff)
examples/l3fwd: fix aliasing in port grouping
With -f-strict-aliasing enabled by default from -O2, gcc > 5.x gives undefined behavior in port_groupx4 in ARM. 'pn' and 'pnum' are two different pointers pointing to same chunk of memory and with -f-strict-aliasing the pointers are assumed to be pointing to different memory and compiler reorders instructions that depend on pnum and pn. This breaks port grouping algorithm. This patch eliminates the above problem by introducing a compiler barrier between the instructions that depend on pnum, pn and lp. Fixes: 569b290cdb36 ("examples/l3fwd: add NEON implementation") Cc: Signed-off-by: Guduri Prathyusha <> Acked-by: Jerin Jacob <> Acked-by: Jianbo Liu <>
Diffstat (limited to 'examples/l3fwd')
1 files changed, 1 insertions, 0 deletions
diff --git a/examples/l3fwd/l3fwd_neon.h b/examples/l3fwd/l3fwd_neon.h
index 4bc1613..b319b5a 100644
--- a/examples/l3fwd/l3fwd_neon.h
+++ b/examples/l3fwd/l3fwd_neon.h
@@ -114,6 +114,7 @@ port_groupx4(uint16_t pn[FWDSTEP + 1], uint16_t *lp, uint16x8_t dp1,
/* update last port counter. */
lp[0] += gptbl[v].lpv;
+ rte_compiler_barrier();
/* if dest port value has changed. */
if (v != GRPMSK) {