From: Zhihong Wang <zhihong.wang@intel.com>
Date: Mon, 18 Jan 2016 03:05:14 +0000 (-0500)
Subject: eal/x86: tune memcpy for platforms without AVX512
X-Git-Tag: spdx-start~7671
X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=1ae817f9f887aae66c185eb9a3a626be0877f9c7;p=dpdk.git

eal/x86: tune memcpy for platforms without AVX512

For prior platforms, add condition for unalignment handling, to keep this
operation from interrupting the batch copy loop for aligned cases.

Signed-off-by: Zhihong Wang <zhihong.wang@intel.com>
---

diff --git a/lib/librte_eal/common/include/arch/x86/rte_memcpy.h b/lib/librte_eal/common/include/arch/x86/rte_memcpy.h
index fee954ada4..d965957956 100644
--- a/lib/librte_eal/common/include/arch/x86/rte_memcpy.h
+++ b/lib/librte_eal/common/include/arch/x86/rte_memcpy.h
@@ -513,10 +513,12 @@ COPY_BLOCK_64_BACK31:
 	 * Make store aligned when copy size exceeds 512 bytes
 	 */
 	dstofss = 32 - ((uintptr_t)dst & 0x1F);
-	n -= dstofss;
-	rte_mov32((uint8_t *)dst, (const uint8_t *)src);
-	src = (const uint8_t *)src + dstofss;
-	dst = (uint8_t *)dst + dstofss;
+	if (dstofss > 0) {
+		n -= dstofss;
+		rte_mov32((uint8_t *)dst, (const uint8_t *)src);
+		src = (const uint8_t *)src + dstofss;
+		dst = (uint8_t *)dst + dstofss;
+	}
 
 	/**
 	 * Copy 256-byte blocks.
@@ -833,11 +835,13 @@ COPY_BLOCK_64_BACK15:
 	 * backwards access.
 	 */
 	dstofss = 16 - ((uintptr_t)dst & 0x0F) + 16;
-	n -= dstofss;
-	rte_mov32((uint8_t *)dst, (const uint8_t *)src);
-	src = (const uint8_t *)src + dstofss;
-	dst = (uint8_t *)dst + dstofss;
-	srcofs = ((uintptr_t)src & 0x0F);
+	if (dstofss > 0) {
+		n -= dstofss;
+		rte_mov32((uint8_t *)dst, (const uint8_t *)src);
+		src = (const uint8_t *)src + dstofss;
+		dst = (uint8_t *)dst + dstofss;
+		srcofs = ((uintptr_t)src & 0x0F);
+	}
 
 	/**
 	 * For aligned copy