[PATCH] perf bench: fix order of arguments to memcpy_alloc_mem

[PATCH] perf bench: fix order of arguments to memcpy_alloc_mem

[Bruce Merry]

This was causing the destination instead of the source to be filled.
As a result, the source was typically all mapped to one zero page,
and hence very cacheable
---
 tools/perf/bench/mem-memcpy.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/bench/mem-memcpy.c b/tools/perf/bench/mem-memcpy.c
index 6c14afe..db1d3a2 100644
--- a/tools/perf/bench/mem-memcpy.c
+++ b/tools/perf/bench/mem-memcpy.c
@@ -289,7 +289,7 @@ static u64 do_memcpy_cycle(const struct routine
*r, size_t len, bool prefault)
     memcpy_t fn = r->fn.memcpy;
     int i;

-    memcpy_alloc_mem(&src, &dst, len);
+    memcpy_alloc_mem(&dst, &src, len);

     if (prefault)
         fn(dst, src, len);
@@ -312,7 +312,7 @@ static double do_memcpy_gettimeofday(const struct
routine *r, size_t len,
     void *src = NULL, *dst = NULL;
     int i;

-    memcpy_alloc_mem(&src, &dst, len);
+    memcpy_alloc_mem(&dst, &src, len);

     if (prefault)
         fn(dst, src, len);
-- 
1.9.1


-- 
Bruce Merry
Senior Science Processing Developer
SKA South Africa

Re: [PATCH] perf bench: fix order of arguments to memcpy_alloc_mem

[Peter Zijlstra]

On Thu, Jan 15, 2015 at 10:15:34AM +0200, Bruce Merry wrote:
> This was causing the destination instead of the source to be filled.
> As a result, the source was typically all mapped to one zero page,
> and hence very cacheable

Almost right ;-)

Please have a look at Documentation/SubmittingPatches

We require at least a Signed-off-by: tag in order to process patches.

Thanks!