[Spice-devel] [PATCH 11/12] add benchmarks for memcpy (RtlCopyMemory) vs fast - fast is slower

Alon Levy alevy at redhat.com
Wed Apr 30 07:40:35 PDT 2014


Two benchmarks:
1. standalone, actually uses LIBCMT's memcpy to compare.
2. Part of qxldd.dll (in display/res.c called from display/driver.c)
so using the same implementation.

Note: next commit removes benchmark code as well as fast_memcpy_* code
and related SSE check and FPU save/restore.

Results for 32 bit windows 7 give ~2 times better performance for
*system* memcpy.
64 bit windows 7 is ~2 times better for size < 128 KByte copies, and
approximately the same for 128 KB <= size <= 1 MB

More complete results:
Note: for 64 bit with 262144 <= size <= 1048576 I got mixed results,
depending on the order of performing the comparison - if memcpy was run
first I got better results for fast_memcpy, by about 20%, for 64 bit
only (for 32 bit memcpy/RtlCopyMemory was still faster).

Windows 7 32 bit:
size [bytes]      our time/system time [percent]
      1024        232
      2048        352
      4096        681
      8192        303
     16384        455
     32768        403
     65536        352
    131072        232
    262144        232
    524288        152
   1048576        177

Windows 7 64 bit:
size [bytes]      our time/system time [percent]
      1024        140
      2048        204
      4096        200
      8192        198
     16384        232
     32768        173
     65536        272
    131072        177
    262144        134
    524288        115
   1048576        115
---
 xddm/display/benchmark_memcpy.c        | 152 +++++++++++++++++++++++++++++++++
 xddm/display/driver.c                  |   4 +
 xddm/display/res.c                     |  57 +++++++++++++
 xddm/tests/benchmark_format_results.py |  38 +++++++++
 xddm/tests/build_benchmark.bat         |   7 ++
 5 files changed, 258 insertions(+)
 create mode 100644 xddm/display/benchmark_memcpy.c
 create mode 100644 xddm/tests/benchmark_format_results.py
 create mode 100644 xddm/tests/build_benchmark.bat

diff --git a/xddm/display/benchmark_memcpy.c b/xddm/display/benchmark_memcpy.c
new file mode 100644
index 0000000..fa44577
--- /dev/null
+++ b/xddm/display/benchmark_memcpy.c
@@ -0,0 +1,152 @@
+#include <windows.h>
+#include <stdio.h>
+
+#ifdef _WIN64
+int have_sse2 = 0;
+void fast_memcpy_aligned(void *dest, const void *src, size_t len);
+#else
+static _inline void fast_memcpy_aligned(void *dest, const void *src, size_t len)
+{
+    _asm
+    {
+        mov ecx, len
+        mov esi, src
+        mov edi, dest
+
+        cmp ecx, 128
+        jb try_to_copy64
+
+        prefetchnta [esi]
+        copy_128:
+            prefetchnta [esi + 64]
+
+            movdqa xmm0, [esi]
+            movdqa xmm1, [esi + 16]
+            movdqa xmm2, [esi + 32]
+            movdqa xmm3, [esi + 48]
+
+            prefetchnta [esi + 128]
+
+            movntdq [edi], xmm0
+            movntdq [edi + 16], xmm1
+            movntdq [edi + 32], xmm2
+            movntdq [edi + 48], xmm3
+
+            movdqa xmm0, [esi + 64]
+            movdqa xmm1, [esi + 80]
+            movdqa xmm2, [esi + 96]
+            movdqa xmm3, [esi + 112]
+
+            movntdq [edi + 64], xmm0
+            movntdq [edi + 80], xmm1
+            movntdq [edi + 96], xmm2
+            movntdq [edi + 112], xmm3
+
+            add edi, 128
+            add esi, 128
+            sub ecx, 128
+            cmp ecx, 128
+            jae copy_128
+
+       try_to_copy64:
+            cmp ecx, 64
+            jb try_to_copy32
+
+             movdqa xmm0, [esi]
+             movdqa xmm1, [esi + 16]
+             movdqa xmm2, [esi + 32]
+             movdqa xmm3, [esi + 48]
+
+             movntdq [edi], xmm0
+             movntdq [edi + 16], xmm1
+             movntdq [edi + 32], xmm2
+             movntdq [edi + 48], xmm3
+
+             add edi, 64
+             add esi, 64
+             sub ecx, 64
+             prefetchnta [esi]
+
+        try_to_copy32:
+             cmp ecx, 32
+             jb try_to_copy16
+
+             movdqa xmm0, [esi]
+             movdqa xmm1, [esi + 16]
+             movntdq [edi], xmm0
+             movntdq [edi + 16], xmm1
+
+             add edi, 32
+             add esi, 32
+             sub ecx, 32
+
+        try_to_copy16:
+             cmp ecx, 16
+             jb try_to_copy4
+
+             movdqa xmm0, [esi]
+             movntdq [edi], xmm0
+
+             add edi, 16
+             add esi, 16
+             sub ecx, 16
+
+
+        try_to_copy4:
+            cmp ecx, 4
+            jb try_to_copy_1
+            movsd
+            sub ecx, 4
+            jmp try_to_copy4
+
+        try_to_copy_1:
+            rep movsb
+
+        sfence
+    }
+}
+#endif
+
+typedef unsigned long long uint64_t;
+
+uint64_t time_usecs(void)
+{
+  SYSTEMTIME systime;
+  GetSystemTime(&systime);
+  return systime.wMilliseconds * 1000 + systime.wSecond * 1e6 + systime.wMinute * 60e6 + systime.wHour * 3600e6;
+}
+
+int main(void)
+{
+  int i;
+  unsigned char *src_unaligned;
+  unsigned char *dest_unaligned;
+  uint64_t start, total1, total2;
+  unsigned char *src = NULL;
+  unsigned char *dest = NULL;
+  size_t size = 1024;
+  size_t iter = 1024 * 1024;
+
+  printf("fast_memcpy compared to memcpy (< 1.0 means memcpy is better)\n");
+  for (size = 1024; size < 1024*1024*2; size *= 2, iter /= 2) {
+    src_unaligned = malloc(size + 15);
+    dest_unaligned = malloc(size + 15);
+    src = (unsigned char *)((size_t)(src_unaligned + 15) & ~0xf);
+    dest = (unsigned char *)((size_t)(dest_unaligned + 15) & ~0xf);
+    start = time_usecs();
+    for (i = 0 ; i < iter ; ++i)
+      memcpy(dest, src, size);
+    total1 = time_usecs() - start;
+
+    start = time_usecs();
+    for (i = 0 ; i < iter ; ++i)
+      fast_memcpy_aligned(dest, src, size);
+    total2 = time_usecs() - start;
+
+    printf("%d: %f (%d, ", size, ((float)total1) / total2, total1);
+    printf("%d)\n", total2);
+    free(src_unaligned);
+    free(dest_unaligned);
+  }
+  return 0;
+}
diff --git a/xddm/display/driver.c b/xddm/display/driver.c
index 5a3dbfa..bed1d58 100644
--- a/xddm/display/driver.c
+++ b/xddm/display/driver.c
@@ -903,6 +903,8 @@ VOID EnableQXLPrimarySurface(PDev *pdev)
     pdev->surf_enable = TRUE;
 }
 
+void benchmark_memcpy(PDev *pdev);
+
 HSURF DrvEnableSurface(DHPDEV in_pdev)
 {
     PDev *pdev;
@@ -941,6 +943,8 @@ HSURF DrvEnableSurface(DHPDEV in_pdev)
 
     EnableQXLPrimarySurface(pdev);
 
+    benchmark_memcpy(pdev);
+
     DEBUG_PRINT((pdev, 1, "%s: 0x%lx exit\n", __FUNCTION__, pdev));
     return surf;
 
diff --git a/xddm/display/res.c b/xddm/display/res.c
index 60e9bcb..589218b 100644
--- a/xddm/display/res.c
+++ b/xddm/display/res.c
@@ -1283,6 +1283,63 @@ static _inline void fast_memcpy_unaligment(void *dest, const void *src, size_t l
 
 #endif
 
+uint64_t time_usecs(void)
+{
+  ENG_TIME_FIELDS systime;
+  EngQueryLocalTime(&systime);
+  return (uint64_t)(systime.usMilliseconds * 1000 + systime.usSecond * 1e6 +
+                     systime.usMinute * 60e6 + systime.usHour * 3600e6);
+}
+
+void benchmark_memcpy(PDev *pdev)
+{
+  size_t i;
+  unsigned char *src_unaligned;
+  unsigned char *dest_unaligned;
+  uint64_t start, total1, total2;
+  unsigned char *src = NULL;
+  unsigned char *dest = NULL;
+  size_t size = 1024;
+  size_t iter = 1024 * 1024;
+
+  for (size = 1024; size < 1024*1024*2; size *= 2, iter /= 2) {
+    src_unaligned = EngAllocMem(0, size + 31, ALLOC_TAG);
+    dest_unaligned = EngAllocMem(0, size + 31, ALLOC_TAG);
+    src = (unsigned char *)((size_t)(src_unaligned + 31) & ~0x1f);
+    dest = (unsigned char *)((size_t)(dest_unaligned + 31) & ~0x1f);
+
+    for (i = 0 ; i < size ; ++i)
+      src[i] = i;
+
+    start = time_usecs();
+    for (i = 0 ; i < iter ; ++i) {
+      fast_memcpy_aligned(dest, src, size);
+    }
+    total2 = time_usecs() - start;
+
+    {
+      int errors = 0;
+      for (i = 0 ; i < size ; ++i) {
+        if (dest[i] != src[i]) {
+          errors++;
+        }
+      }
+      if (errors > 0) {
+        DEBUG_PRINT((pdev, 1, "!!! copy errors %d !!!\n", errors));
+      }
+    }
+
+    start = time_usecs();
+    for (i = 0 ; i < iter ; ++i)
+      memcpy(dest, src, size);
+    total1 = time_usecs() - start;
+
+    DEBUG_PRINT((pdev, 1, "%d: %lld, %lld\n", size, total1, total2));
+    EngFreeMem(src_unaligned);
+    EngFreeMem(dest_unaligned);
+  }
+}
+
 #ifdef DBG
     #define PutBytesAlign __PutBytesAlign
 #define PutBytes(pdev, chunk, now, end, src, size, page_counter, alloc_size, use_sse)\
diff --git a/xddm/tests/benchmark_format_results.py b/xddm/tests/benchmark_format_results.py
new file mode 100644
index 0000000..96d302b
--- /dev/null
+++ b/xddm/tests/benchmark_format_results.py
@@ -0,0 +1,38 @@
+import sys
+
+win7_32="""qxl/guest-0: 96463384453: qxldd: 1024: 47000, 109000
+qxl/guest-0: 96591785177: qxldd: 2048: 31000, 109000
+qxl/guest-0: 96722899152: qxldd: 4096: 16000, 109000
+qxl/guest-0: 96851422238: qxldd: 8192: 31000, 94000
+qxl/guest-0: 97013842048: qxldd: 16384: 31000, 141000
+qxl/guest-0: 97167323122: qxldd: 32768: 31000, 125000
+qxl/guest-0: 97316872306: qxldd: 65536: 31000, 109000
+qxl/guest-0: 97465747407: qxldd: 131072: 47000, 109000
+qxl/guest-0: 97624668249: qxldd: 262144: 47000, 109000
+qxl/guest-0: 97785876639: qxldd: 524288: 62000, 94000
+qxl/guest-0: 97953480643: qxldd: 1048576: 62000, 110000
+"""
+
+win7_64="""
+qxl/guest-0: 2278149101498: qxldd: 1024: 78000, 109000
+qxl/guest-0: 2278288271327: qxldd: 2048: 46000, 94000
+qxl/guest-0: 2278428135167: qxldd: 4096: 47000, 94000
+qxl/guest-0: 2278575078269: qxldd: 8192: 47000, 93000
+qxl/guest-0: 2278734906600: qxldd: 16384: 47000, 109000
+qxl/guest-0: 2278896881683: qxldd: 32768: 63000, 109000
+qxl/guest-0: 2279073699223: qxldd: 65536: 46000, 125000
+qxl/guest-0: 2279250403663: qxldd: 131072: 62000, 110000
+qxl/guest-0: 2279467314681: qxldd: 262144: 93000, 125000
+qxl/guest-0: 2279693375414: qxldd: 524288: 109000, 125000
+qxl/guest-0: 2279929972847: qxldd: 1048576: 109000, 125000
+"""
+
+filt = lambda txt: filt2(filt1(txt))
+filt2 = lambda data: [(s, system, ours*100.0/system) for t, s, system, ours in data]
+filt1 = lambda txt: map(lambda a: (int(a[1][:-1]), int(a[3][:-1]), int(a[4][:-1]), int(a[5])), map(lambda l: l.strip().split(), [l for l in txt.split('\n') if l.strip() != '']))
+display = lambda txt: sys.stdout.write('\n'.join('%10s %10s' % (a, '%3.0f' % c) for a, b, c in filt(txt))+'\n')
+
+print('size [bytes]'.ljust(18) + 'our time/system time [percent]')
+display(win7_32)
+print('size [bytes]'.ljust(18) + 'our time/system time [percent]')
+display(win7_64)
diff --git a/xddm/tests/build_benchmark.bat b/xddm/tests/build_benchmark.bat
new file mode 100644
index 0000000..a184249
--- /dev/null
+++ b/xddm/tests/build_benchmark.bat
@@ -0,0 +1,7 @@
+cl /Zi /nologo /c /I %CRT_INC_PATH% ..\display\benchmark_memcpy.c
+if defined AMD64 (
+ml64 /c /Zd ..\display\amd64\x64.asm
+link /nologo /debug /libpath:%BASEDIR%\lib\crt\amd64\ /libpath:%DDK_LIB_DEST%\amd64 x64.obj benchmark_memcpy.obj
+) else (
+link /nologo /debug /libpath:%BASEDIR%\lib\crt\i386\ /libpath:%DDK_LIB_DEST%\i386 benchmark_memcpy.obj
+)
-- 
1.9.0



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