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authorRay Kinsella <ray.kinsella@intel.com>2017-04-21 11:08:43 +0100
committerRay Kinsella <ray.kinsella@intel.com>2017-04-21 11:26:39 +0100
commit658efd2fc986bca88336569b2e6fa8b537a660d8 (patch)
tree281381215b1d9870b7963521baf17f870025ba36
parent2f2db1c2021c5aae564d2783a33366527afb5fce (diff)
vppinfra: clib_memcpy improvement
In the case where n is a constant 16 bytes, the second load/store is ignored by the load/store unit - it has neglible/zero cost. In the case where n is variable and greater than 512 bytes, the extra if (n == 16) branch has a very small performance impact. Change-Id: I04b313cf022c18fee31b1d9bcf6a128414659a99 Signed-off-by: Ray Kinsella <ray.kinsella@intel.com>
-rw-r--r--src/vppinfra/memcpy_avx.h5
-rw-r--r--src/vppinfra/memcpy_sse3.h5
2 files changed, 0 insertions, 10 deletions
diff --git a/src/vppinfra/memcpy_avx.h b/src/vppinfra/memcpy_avx.h
index d95bbad72b8..e3feb76b6b7 100644
--- a/src/vppinfra/memcpy_avx.h
+++ b/src/vppinfra/memcpy_avx.h
@@ -185,11 +185,6 @@ clib_memcpy (void *dst, const void *src, size_t n)
/**
* Fast way when copy size doesn't exceed 512 bytes
*/
- if (n == 16)
- {
- clib_mov16 ((u8 *) dst, (const u8 *) src);
- return ret;
- }
if (n <= 32)
{
clib_mov16 ((u8 *) dst, (const u8 *) src);
diff --git a/src/vppinfra/memcpy_sse3.h b/src/vppinfra/memcpy_sse3.h
index 49baf5e5d31..4fc48c86c8b 100644
--- a/src/vppinfra/memcpy_sse3.h
+++ b/src/vppinfra/memcpy_sse3.h
@@ -224,11 +224,6 @@ clib_memcpy (void *dst, const void *src, size_t n)
/**
* Fast way when copy size doesn't exceed 512 bytes
*/
- if (n == 16)
- {
- clib_mov16 ((u8 *) dst, (const u8 *) src);
- return ret;
- }
if (n <= 32)
{
clib_mov16 ((u8 *) dst, (const u8 *) src);