Re: [PATCH 3/8] generic/192: fix spurious timeout

Darrick J. Wong
2024-02-27T04:29:44Z

On Tue, Feb 27, 2024 at 12:23:46PM +0800, Zorro Lang wrote:
> On Mon, Feb 26, 2024 at 06:01:19PM -0800, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> >
> > I have a theory that when the nfs server that hosts the root fs for my
> > testing VMs gets backed up, it can take a while for path resolution and
> > loading of echo, cat, or tee to finish. That delays the test enough to
> > result in:
> >
> > --- /tmp/fstests/tests/generic/192.out 2023-11-29 15:40:52.715517458 -0800
> > +++ /var/tmp/fstests/generic/192.out.bad 2023-12-15 21:28:02.860000000 -0800
> > @@ -1,5 +1,6 @@
> > QA output created by 192
> > sleep for 5 seconds
> > test
> > -delta1 is in range
> > +delta1 has value of 12
> > +delta1 is NOT in range 5 .. 7
> > delta2 is in range
>
>
>
> >
> > Therefore, invoke all these utilities with --help before the critical
> > section to make sure they're all in memory.
> >
> > Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> > ---
>
> This patch makes sense to me,
> Reviewed-by: Zorro Lang <zlang@redhat.com>
>
> Just better to give 1 or 2 whitespaces to diff output message (especially the
> lines with "+") in commit log :) I always need to change that manually before
> merge the patch :-D

Oh, you mean indenting the diff output in the commit message?

Yeah, I'll try to remember that from now on:

I have a theory that when the nfs server that hosts the root fs for my
testing VMs gets backed up, it can take a while for path resolution and
loading of echo, cat, or tee to finish. That delays the test enough to
result in:

--- /tmp/fstests/tests/generic/192.out 2023-11-29 15:40:52.715517458 -0800
+++ /var/tmp/fstests/generic/192.out.bad 2023-12-15 21:28:02.860000000 -0800
@@ -1,5 +1,6 @@
QA output created by 192
sleep for 5 seconds
test
-delta1 is in range
+delta1 has value of 12
+delta1 is NOT in range 5 .. 7
delta2 is in range

Therefore, invoke all these utilities with --help before the critical
section to make sure they're all in memory.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

--D

> Thanks,
> Zorro
>
> > tests/generic/192 | 16 +++++++++++++---
> > 1 file changed, 13 insertions(+), 3 deletions(-)
> >
> >
> > diff --git a/tests/generic/192 b/tests/generic/192
> > index 0d3cd03b4b..2825486635 100755
> > --- a/tests/generic/192
> > +++ b/tests/generic/192
> > @@ -29,17 +29,27 @@ delay=5
> > testfile=$TEST_DIR/testfile
> > rm -f $testfile
> >
> > +# Preload every binary used between sampling time1 and time2 so that loading
> > +# them has minimal overhead even if the root fs is hosted over a slow network.
> > +# Also don't put pipe and tee creation in that critical section.
> > +for i in echo stat sleep cat; do
> > + $i --help &>/dev/null
> > +done
> > +
> > echo test >$testfile
> > -time1=`_access_time $testfile | tee -a $seqres.full`
> > +time1=`_access_time $testfile`
> > +echo $time1 >> $seqres.full
> >
> > echo "sleep for $delay seconds"
> > sleep $delay # sleep to allow time to move on for access
> > cat $testfile
> > -time2=`_access_time $testfile | tee -a $seqres.full`
> > +time2=`_access_time $testfile`
> > +echo $time2 >> $seqres.full
> >
> > cd /
> > _test_cycle_mount
> > -time3=`_access_time $testfile | tee -a $seqres.full`
> > +time3=`_access_time $testfile`
> > +echo $time3 >> $seqres.full
> >
> > delta1=`expr $time2 - $time1`
> > delta2=`expr $time3 - $time1`
> >
>
>