From e33a91629509ebb746370b023f63d9f2097d770d Mon Sep 17 00:00:00 2001
From: Andrea Mazzoleni <amadvance@gmail.com>
Date: Mon, 7 Oct 2013 22:21:26 +0200
Subject: [PATCH] Disables SSSE3 on Atom and Jaguar CPU. It's slower than plain
 SSE2.

---
 cpu.h   | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 raid.c  |  2 +-
 speed.c |  7 ++++---
 3 files changed, 69 insertions(+), 5 deletions(-)

diff --git a/cpu.h b/cpu.h
index a1ed93f0..76c29b8a 100644
--- a/cpu.h
+++ b/cpu.h
@@ -156,6 +156,70 @@ static inline int cpu_has_slowmult(void)
 	return 0;
 }
 
+/**
+ * Check if the processor has a slow PSHUFB implementation.
+ * If yes, it's better to not use it.
+ */
+static inline int cpu_has_slowpshufb(void)
+{
+	char vendor[CPU_VENDOR_MAX];
+	unsigned family;
+	unsigned model;
+
+	cpu_info(vendor, &family, &model);
+
+	if (strcmp(vendor, "GenuineIntel") == 0) {
+		/* Intel ATOM (info from x264 -> full family/model 6/28) */
+
+		/* Intel(R) Atom(TM) CPU D525 @ 1.80GHz (info from user)
+		 * Compiler gcc 4.7.2
+		 * CPU GenuineIntel, family 6, model 28, flags mmx sse2 ssse3 slowmult
+		 * Memory is little-endian 64-bit
+		 * Support nanosecond timestamps with futimens()
+		 * 
+		 * Speed test with 8 disk and 262144 buffer size, for a total of 2816 KiB...
+		 * memset0 1850 [MB/s]
+		 * CRC table 316 [MB/s]
+		 * HASH Murmur3 378 [MB/s]
+		 * HASH Spooky2 3389 [MB/s]
+		 * RAID5 int32 1800 [MB/s]
+		 * RAID5 int64 2938 [MB/s]
+		 * RAID5 mmx 2946 [MB/s]
+		 * RAID5 sse2 3429 [MB/s]
+		 * RAID5 sse2ext 3447 [MB/s]
+		 * RAID6 int32 519 [MB/s]
+		 * RAID6 int64 944 [MB/s]
+		 * RAID6 mmx 1160 [MB/s]
+		 * RAID6 sse2 2082 [MB/s]
+		 * RAID6 sse2ext 2481 [MB/s]
+		 * RAIDTP int32 236 [MB/s]
+		 * RAIDTP int64 456 [MB/s]
+		 * RAIDTP mmx 576 [MB/s]
+		 * RAIDTP sse2 1109 [MB/s]
+		 * RAIDTP sse2ext 1527 [MB/s]
+		 * RAIDTP ssse3 931 [MB/s] (slower than sse2ext)
+		 * RAIDTP ssse3ext 932 [MB/s] (slower than sse2ext)
+		 * RAIDQP int32 144 [MB/s]
+		 * RAIDQP int64 271 [MB/s]
+		 * RAIDQP mmx 431 [MB/s]
+		 * RAIDQP sse2 843 [MB/s]
+		 * RAIDQP sse2ext 1086 [MB/s]
+		 * RAIDQP ssse3 732 [MB/s] (slower than sse2ext)
+		 * RAIDQP ssse3ext 571 [MB/s] (slower than sse2ext)
+		 */
+		if (family == 6 && model == 28)
+			return 1;
+	}
+
+	if (strcmp(vendor, "AuthenticAMD") == 0) {
+		/* AMD Jaguar (info from x264 -> full family 0x16==21) */
+		if (family == 21)
+			return 1;
+	}
+
+	return 0;
+}
+
 /**
  * Check if the processor has a slow extended set of SSE registers.
  * If yes, it's better to unroll without using the second part of registers.
@@ -196,7 +260,6 @@ static inline int cpu_has_slowextendedreg(void)
 	return 0;
 }
 
-
 /* other cases */
 
 /* Intel(R) Core(TM) i7-3740QM CPU @ 2.70GHz
diff --git a/raid.c b/raid.c
index 5b5f71f9..fae10f6b 100644
--- a/raid.c
+++ b/raid.c
@@ -2914,7 +2914,7 @@ void raid_init(void)
 #endif
 	}
 
-	if (cpu_has_ssse3()) {
+	if (cpu_has_ssse3() && !cpu_has_slowpshufb()) {
 #if defined(__x86_64__)
 		raidTP_gen = raidTP_ssse3ext;
 		raidQP_gen = raidQP_ssse3ext;
diff --git a/speed.c b/speed.c
index 841ada4f..2f0a54a1 100644
--- a/speed.c
+++ b/speed.c
@@ -89,13 +89,14 @@ void speed(void)
 
 		cpu_info(vendor, &family, &model);
 
-		printf("CPU %s, family %u, model %u, flags%s%s%s%s%s%s\n", vendor, family, model,
+		printf("CPU %s, family %u, model %u, flags%s%s%s%s%s%s%s\n", vendor, family, model,
 			cpu_has_mmx() ? " mmx" : "",
 			cpu_has_sse2() ? " sse2" : "",
 			cpu_has_ssse3() ? " ssse3" : "",
 			cpu_has_sse42() ? " sse42" : "",
 			cpu_has_avx() ? " avx" : "",
-			cpu_has_slowmult() ? " slowmult" : ""
+			cpu_has_slowmult() ? " slowmult" : "",
+			cpu_has_slowpshufb()  ? " slowpshufb" : ""
 			);
 	}
 #else
@@ -335,7 +336,7 @@ void speed(void)
 			raidQP_mmx(buffer, diskmax, block_size);
 		} SPEED_STOP
 
-		printf("RAIDQP mmxr1 %"PRIu64" [MB/s]\n", ds / dt);
+		printf("RAIDQP mmx %"PRIu64" [MB/s]\n", ds / dt);
 	}
 
 	if (cpu_has_sse2()) {