diff mbox series

[RFC] selftests/vm/transhuge-stress: fix ram size thinko

Message ID 20210825135843.29052-1-george_davis@mentor.com
State New
Headers show
Series [RFC] selftests/vm/transhuge-stress: fix ram size thinko | expand

Commit Message

George G. Davis Aug. 25, 2021, 1:58 p.m. UTC
From: "George G. Davis" <davis.george@siemens.com>

When executing transhuge-stress with an argument to specify the virtual
memory size for testing, the ram size is reported as 0, e.g.

transhuge-stress 384
thp-mmap: allocate 192 transhuge pages, using 384 MiB virtual memory and 0 MiB of ram
thp-mmap: 0.184 s/loop, 0.957 ms/page,   2090.265 MiB/s  192 succeed,    0 failed

This appears to be due to a thinko in commit 0085d61fe05e
("selftests/vm/transhuge-stress: stress test for memory compaction"),
where, at a guess, the intent was to base "xyz MiB of ram" on `ram`
size. Here are results after using `ram` size:

thp-mmap: allocate 192 transhuge pages, using 384 MiB virtual memory and 14 MiB of ram

Fixes: 0085d61fe05e ("selftests/vm/transhuge-stress: stress test for memory compaction")
Signed-off-by: George G. Davis <davis.george@siemens.com>
---
 tools/testing/selftests/vm/transhuge-stress.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

George G. Davis Sept. 28, 2021, 5:58 p.m. UTC | #1
On Wed, Aug 25, 2021 at 09:58:43AM -0400, George G. Davis wrote:
> From: "George G. Davis" <davis.george@siemens.com>

> 

> When executing transhuge-stress with an argument to specify the virtual

> memory size for testing, the ram size is reported as 0, e.g.

> 

> transhuge-stress 384

> thp-mmap: allocate 192 transhuge pages, using 384 MiB virtual memory and 0 MiB of ram

> thp-mmap: 0.184 s/loop, 0.957 ms/page,   2090.265 MiB/s  192 succeed,    0 failed

> 

> This appears to be due to a thinko in commit 0085d61fe05e

> ("selftests/vm/transhuge-stress: stress test for memory compaction"),

> where, at a guess, the intent was to base "xyz MiB of ram" on `ram`

> size. Here are results after using `ram` size:

> 

> thp-mmap: allocate 192 transhuge pages, using 384 MiB virtual memory and 14 MiB of ram

> 

> Fixes: 0085d61fe05e ("selftests/vm/transhuge-stress: stress test for memory compaction")

> Signed-off-by: George G. Davis <davis.george@siemens.com>

> ---

>  tools/testing/selftests/vm/transhuge-stress.c | 2 +-

>  1 file changed, 1 insertion(+), 1 deletion(-)

> 

> diff --git a/tools/testing/selftests/vm/transhuge-stress.c b/tools/testing/selftests/vm/transhuge-stress.c

> index fd7f1b4a96f9..5e4c036f6ad3 100644

> --- a/tools/testing/selftests/vm/transhuge-stress.c

> +++ b/tools/testing/selftests/vm/transhuge-stress.c

> @@ -79,7 +79,7 @@ int main(int argc, char **argv)

>  

>  	warnx("allocate %zd transhuge pages, using %zd MiB virtual memory"

>  	      " and %zd MiB of ram", len >> HPAGE_SHIFT, len >> 20,

> -	      len >> (20 + HPAGE_SHIFT - PAGE_SHIFT - 1));

> +	      ram >> (20 + HPAGE_SHIFT - PAGE_SHIFT - 1));


Ping, any comments on this?

For the record, as noted, the value reported for "ram size" appears to
use the wrong variable, `len`, where `ram` should be used instead.

>  

>  	pagemap_fd = open("/proc/self/pagemap", O_RDONLY);

>  	if (pagemap_fd < 0)

> -- 

> 2.17.1

> 


-- 
Regards,
George
diff mbox series

Patch

diff --git a/tools/testing/selftests/vm/transhuge-stress.c b/tools/testing/selftests/vm/transhuge-stress.c
index fd7f1b4a96f9..5e4c036f6ad3 100644
--- a/tools/testing/selftests/vm/transhuge-stress.c
+++ b/tools/testing/selftests/vm/transhuge-stress.c
@@ -79,7 +79,7 @@  int main(int argc, char **argv)
 
 	warnx("allocate %zd transhuge pages, using %zd MiB virtual memory"
 	      " and %zd MiB of ram", len >> HPAGE_SHIFT, len >> 20,
-	      len >> (20 + HPAGE_SHIFT - PAGE_SHIFT - 1));
+	      ram >> (20 + HPAGE_SHIFT - PAGE_SHIFT - 1));
 
 	pagemap_fd = open("/proc/self/pagemap", O_RDONLY);
 	if (pagemap_fd < 0)