[LTP] [PATCH] dio: reduce the number of cycles

[LTP] [PATCH] dio: reduce the number of cycles

[Li Wang]

These two cases (dio29/30) takes a bit long time in dio test, but they're not stress
test, so I suggest reducing the number of cycles.

On my RHEL-7.3 (23G RAM, 24 CPU(s), x86_64) box, it takes almost 9 mins.

  diotest06    1  TPASS  :  Read with Direct IO, Write without
  diotest06    2  TPASS  :  Write with Direct IO, Read without
  diotest06    3  TPASS  :  Read, Write with Direct IO
  diotest06    0  TINFO  :  3 testblocks 1000 iterations with 100 children completed

  real	8m4.805s
  user	71m36.722s
  sys	8m51.649s

Signed-off-by: Li Wang <liwang@redhat.com>
---
 runtest/dio | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/runtest/dio b/runtest/dio
index a26e001..185cd57 100644
--- a/runtest/dio
+++ b/runtest/dio
@@ -40,8 +40,8 @@ dio27 diotest6 -b 8192 -o 1024000 -i 1000 -v 100
 dio28 diotest6 -b 8192 -o 1024000 -i 1000 -v 200
 
 ### Run the tests with more children
-dio29 diotest3 -b 65536 -n 100 -i 1000 -o 1024000
-dio30 diotest6 -b 65536 -n 100 -i 1000 -o 1024000
+dio29 diotest3 -b 65536 -n 100 -i 100 -o 1024000
+dio30 diotest6 -b 65536 -n 100 -i 100 -o 1024000
 #
 # RAW DEVICE TEST SECTION
 #   DEV1 and DEV2 should be exported prior to execution or
-- 
2.9.3

[LTP] [PATCH] dio: reduce the number of cycles

[Eryu Guan]

On Wed, Jun 14, 2017 at 11:38:30AM +0800, Li Wang wrote:
> These two cases (dio29/30) takes a bit long time in dio test, but they're not stress
> test, so I suggest reducing the number of cycles.
> 
> On my RHEL-7.3 (23G RAM, 24 CPU(s), x86_64) box, it takes almost 9 mins.
> 
>   diotest06    1  TPASS  :  Read with Direct IO, Write without
>   diotest06    2  TPASS  :  Write with Direct IO, Read without
>   diotest06    3  TPASS  :  Read, Write with Direct IO
>   diotest06    0  TINFO  :  3 testblocks 1000 iterations with 100 children completed
> 
>   real	8m4.805s
>   user	71m36.722s
>   sys	8m51.649s
> 
> Signed-off-by: Li Wang <liwang@redhat.com>

I tested diotest30 with 100 iterations and it still could reproduce the
bug I was seeing on 4.10 kernel quite reliably (even if not 100%), so

Acked-by: Eryu Guan <eguan@redhat.com>

> ---
>  runtest/dio | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/runtest/dio b/runtest/dio
> index a26e001..185cd57 100644
> --- a/runtest/dio
> +++ b/runtest/dio
> @@ -40,8 +40,8 @@ dio27 diotest6 -b 8192 -o 1024000 -i 1000 -v 100
>  dio28 diotest6 -b 8192 -o 1024000 -i 1000 -v 200
>  
>  ### Run the tests with more children
> -dio29 diotest3 -b 65536 -n 100 -i 1000 -o 1024000
> -dio30 diotest6 -b 65536 -n 100 -i 1000 -o 1024000
> +dio29 diotest3 -b 65536 -n 100 -i 100 -o 1024000
> +dio30 diotest6 -b 65536 -n 100 -i 100 -o 1024000
>  #
>  # RAW DEVICE TEST SECTION
>  #   DEV1 and DEV2 should be exported prior to execution or
> -- 
> 2.9.3
> 

[LTP] [PATCH] dio: reduce the number of cycles

[Cyril Hrubis]

Hi!
> I tested diotest30 with 100 iterations and it still could reproduce the
> bug I was seeing on 4.10 kernel quite reliably (even if not 100%), so
> 
> Acked-by: Eryu Guan <eguan@redhat.com>

What's the reliability after the patch btw? What is the actual
percentage of undetected failures for at least 10 runs of the test?

-- 
Cyril Hrubis
chrubis@suse.cz

[LTP] [PATCH] dio: reduce the number of cycles

[Eryu Guan]

On Wed, Jun 14, 2017 at 03:49:39PM +0200, Cyril Hrubis wrote:
> Hi!
> > I tested diotest30 with 100 iterations and it still could reproduce the
> > bug I was seeing on 4.10 kernel quite reliably (even if not 100%), so
> > 
> > Acked-by: Eryu Guan <eguan@redhat.com>
> 
> What's the reliability after the patch btw? What is the actual
> percentage of undetected failures for at least 10 runs of the test?

I ran diotest30 10 times with "-i 100" and 8 of them failed. IIRC, it
was not 100% reproduced either when I first saw the test failure in
4.10-rc kernel testing. So I think ~80% probability to reproduce is
fine.

Thanks,
Eryu

[LTP] [PATCH] dio: reduce the number of cycles

[Cyril Hrubis]

Hi!
> > What's the reliability after the patch btw? What is the actual
> > percentage of undetected failures for at least 10 runs of the test?
> 
> I ran diotest30 10 times with "-i 100" and 8 of them failed. IIRC, it
> was not 100% reproduced either when I first saw the test failure in
> 4.10-rc kernel testing. So I think ~80% probability to reproduce is
> fine.

Fair enough I've added this paragraph to the commit message and pushed,
thanks.

-- 
Cyril Hrubis
chrubis@suse.cz

[LTP] [PATCH] dio: reduce the number of cycles

[Li Wang]

On Thu, Jun 15, 2017 at 5:23 PM, Cyril Hrubis <chrubis@suse.cz> wrote:
> Hi!
>> > What's the reliability after the patch btw? What is the actual
>> > percentage of undetected failures for at least 10 runs of the test?
>>
>> I ran diotest30 10 times with "-i 100" and 8 of them failed. IIRC, it
>> was not 100% reproduced either when I first saw the test failure in
>> 4.10-rc kernel testing. So I think ~80% probability to reproduce is
>> fine.
>
> Fair enough I've added this paragraph to the commit message and pushed,
> thanks.

Hmm, it does not takes about 100 minutes, without this change, it
takes almost 9mins. After applying, only 50secs.

That's probably my description misleading you, sorry about that. Since
you have already submitted this patch, so, let it go.


=============
commit b246897a5a8e31b47442d15d7854a0eb8e64e949
Author: Li Wang <liwang@redhat.com>
Date:   Wed Jun 14 11:38:30 2017 +0800

    dio: reduce the number of cycles

    These two cases (dio29/30) takes about 100 minutes, but they're not
    stress test, so I suggest reducing the number of cycles.

    After the change on my RHEL-7.3 (23G RAM, 24 CPU(s), x86_64) box, it
    still takes almost 9 mins.

      diotest06    1  TPASS  :  Read with Direct IO, Write without
      diotest06    2  TPASS  :  Write with Direct IO, Read without
      diotest06    3  TPASS  :  Read, Write with Direct IO
      diotest06    0  TINFO  :  3 testblocks 1000 iterations with 100
children completed

      real  8m4.805s
      user  71m36.722s
      sys   8m51.649s

==============




-- 
Li Wang
liwang@redhat.com

[LTP] [PATCH] dio: reduce the number of cycles

[Cyril Hrubis]

Hi!
> >> > What's the reliability after the patch btw? What is the actual
> >> > percentage of undetected failures for at least 10 runs of the test?
> >>
> >> I ran diotest30 10 times with "-i 100" and 8 of them failed. IIRC, it
> >> was not 100% reproduced either when I first saw the test failure in
> >> 4.10-rc kernel testing. So I think ~80% probability to reproduce is
> >> fine.
> >
> > Fair enough I've added this paragraph to the commit message and pushed,
> > thanks.
> 
> Hmm, it does not takes about 100 minutes, without this change, it
> takes almost 9mins. After applying, only 50secs.
> 
> That's probably my description misleading you, sorry about that. Since
> you have already submitted this patch, so, let it go.

Strange, it does take about ~10 minutes after the patch is applied for
me and about ~100 before at least for diotest6, diotest3 is a bit faster
with ~20 minutes before and ~4 minutes after. That is on NUMA machine
with 24 CPUs and 16GB RAM and /tmp on Btrfs.

The diotest6 appears to be taking about ~45 minutes in our automated
framework before this patch and diotest3 takes about 3 minutes.

On my workstation the diotest3 takes ~5 minutes after the patch and
diotest06 takes ~45 minutes. That is much more modest machine with just
4GB RAM and 4 CPUs.

So I would say that the resulting time depends on many factors, most
notably the underlying I/O device, fileystem, number of CPUs and RAM.

-- 
Cyril Hrubis
chrubis@suse.cz