[PATCH 2/2] xfs/216: disable all concurrency scaling

[PATCH 2/2] xfs/216: disable all concurrency scaling

[Christoph Hellwig]

This test currently disables log concurrency scaling, but even the
data device concurrency scaling can create mismatching output on
systems with a large CPU count.

Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 tests/xfs/216 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/xfs/216 b/tests/xfs/216
index 1749647c11f7..ce8bb528410b 100755
--- a/tests/xfs/216
+++ b/tests/xfs/216
@@ -23,7 +23,7 @@ _cleanup()
 _require_scratch
 _scratch_mkfs_xfs >/dev/null 2>&1
 if _scratch_mkfs_xfs_supports_concurrency -l >> $seqres.full 2>&1; then
-	loop_mkfs_opts="-l concurrency=0"
+	loop_mkfs_opts="-d concurrency=0 -l concurrency=0 -r concurrency=0"
 else
 	loop_mkfs_opts=""
 fi
-- 
2.53.0

Re: [PATCH 2/2] xfs/216: disable all concurrency scaling

[Shin'ichiro Kawasaki]

On Jun 18, 2026 / 15:48, Christoph Hellwig wrote:
> This test currently disables log concurrency scaling, but even the
> data device concurrency scaling can create mismatching output on
> systems with a large CPU count.
> 
> Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Thanks, I confirmed this patch avoid the failure that I reported.

Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>

cpu scaling fixes v2

[Christoph Hellwig]

Hi all,

this series fully disables the mkfs automatic CPU count scaling for two
tests, where that would lead to differences in the gold output.

Changes since v1:
 - only disabling scaling in xfs/078 when it is supported

[PATCH 1/2] xfs/078: disable all concurrency scaling

[Christoph Hellwig]

Disable concurrency scaling to avoid mismatching output on systems with
a large CPU count.

Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
---
 tests/xfs/078 | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/tests/xfs/078 b/tests/xfs/078
index 6057aeea12ab..408170ae57f5 100755
--- a/tests/xfs/078
+++ b/tests/xfs/078
@@ -57,9 +57,16 @@ _grow_loop()
 	$XFS_IO_PROG -f -c "truncate $original" $LOOP_IMG
 	loop_dev=`_create_loop_device $LOOP_IMG $bsize`
 
-	dparam=""
+	# Disable concurrency scaling to avoid output differences due to large
+	# CPU counts.
+	if _scratch_mkfs_xfs_supports_concurrency -l >> $seqres.full 2>&1; then
+		mkfs_opts="-d concurrency=0 -l concurrency=0 -r concurrency=0"
+	else
+		mkfs_opts=""
+	fi
+
 	if [ -n "$agsize" ]; then
-		dparam="-d agsize=$agsize"
+		mkfs_opts="$mkfs_opts -d agsize=$agsize"
 	fi
 
 	echo
@@ -67,7 +74,7 @@ _grow_loop()
 	echo
 
 	echo "*** mkfs loop file (size=$original)"
-	$MKFS_XFS_PROG -b size=$bsize $dparam $loop_dev | \
+	$MKFS_XFS_PROG -b size=$bsize $mkfs_opts $loop_dev | \
 		_filter_mkfs 2>/dev/null
 
 	echo "*** extend loop file"
-- 
2.53.0

[PATCH 2/2] xfs/216: disable all concurrency scaling

[Christoph Hellwig]

This test currently disables log concurrency scaling, but even the
data device concurrency scaling can create mismatching output on
systems with a large CPU count.

Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
---
 tests/xfs/216 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/xfs/216 b/tests/xfs/216
index 1749647c11f7..ce8bb528410b 100755
--- a/tests/xfs/216
+++ b/tests/xfs/216
@@ -23,7 +23,7 @@ _cleanup()
 _require_scratch
 _scratch_mkfs_xfs >/dev/null 2>&1
 if _scratch_mkfs_xfs_supports_concurrency -l >> $seqres.full 2>&1; then
-	loop_mkfs_opts="-l concurrency=0"
+	loop_mkfs_opts="-d concurrency=0 -l concurrency=0 -r concurrency=0"
 else
 	loop_mkfs_opts=""
 fi
-- 
2.53.0

Re: [PATCH 1/2] xfs/078: disable all concurrency scaling

[Eric Sandeen]

On 6/19/26 12:09 AM, Christoph Hellwig wrote:
> Disable concurrency scaling to avoid mismatching output on systems with
> a large CPU count.
> 
> Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>

Reviewed-by: Eric Sandeen <sandeen@redhat.com>

> ---
>  tests/xfs/078 | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/tests/xfs/078 b/tests/xfs/078
> index 6057aeea12ab..408170ae57f5 100755
> --- a/tests/xfs/078
> +++ b/tests/xfs/078
> @@ -57,9 +57,16 @@ _grow_loop()
>  	$XFS_IO_PROG -f -c "truncate $original" $LOOP_IMG
>  	loop_dev=`_create_loop_device $LOOP_IMG $bsize`
>  
> -	dparam=""
> +	# Disable concurrency scaling to avoid output differences due to large
> +	# CPU counts.
> +	if _scratch_mkfs_xfs_supports_concurrency -l >> $seqres.full 2>&1; then
> +		mkfs_opts="-d concurrency=0 -l concurrency=0 -r concurrency=0"
> +	else
> +		mkfs_opts=""
> +	fi
> +
>  	if [ -n "$agsize" ]; then
> -		dparam="-d agsize=$agsize"
> +		mkfs_opts="$mkfs_opts -d agsize=$agsize"
>  	fi
>  
>  	echo
> @@ -67,7 +74,7 @@ _grow_loop()
>  	echo
>  
>  	echo "*** mkfs loop file (size=$original)"
> -	$MKFS_XFS_PROG -b size=$bsize $dparam $loop_dev | \
> +	$MKFS_XFS_PROG -b size=$bsize $mkfs_opts $loop_dev | \
>  		_filter_mkfs 2>/dev/null
>  
>  	echo "*** extend loop file"

Re: [PATCH 2/2] xfs/216: disable all concurrency scaling

[Eric Sandeen]

On 6/19/26 12:09 AM, Christoph Hellwig wrote:
> This test currently disables log concurrency scaling, but even the
> data device concurrency scaling can create mismatching output on
> systems with a large CPU count.
> 
> Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>

Reviewed-by: Eric Sandeen <sandeen@redhat.com>

> ---
>  tests/xfs/216 | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tests/xfs/216 b/tests/xfs/216
> index 1749647c11f7..ce8bb528410b 100755
> --- a/tests/xfs/216
> +++ b/tests/xfs/216
> @@ -23,7 +23,7 @@ _cleanup()
>  _require_scratch
>  _scratch_mkfs_xfs >/dev/null 2>&1
>  if _scratch_mkfs_xfs_supports_concurrency -l >> $seqres.full 2>&1; then
> -	loop_mkfs_opts="-l concurrency=0"
> +	loop_mkfs_opts="-d concurrency=0 -l concurrency=0 -r concurrency=0"
>  else
>  	loop_mkfs_opts=""
>  fi

Re: [PATCH 2/2] xfs/216: disable all concurrency scaling

[Darrick J. Wong]

On Fri, Jun 19, 2026 at 07:09:29AM +0200, Christoph Hellwig wrote:
> This test currently disables log concurrency scaling, but even the
> data device concurrency scaling can create mismatching output on
> systems with a large CPU count.
> 
> Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> ---
>  tests/xfs/216 | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tests/xfs/216 b/tests/xfs/216
> index 1749647c11f7..ce8bb528410b 100755
> --- a/tests/xfs/216
> +++ b/tests/xfs/216
> @@ -23,7 +23,7 @@ _cleanup()
>  _require_scratch
>  _scratch_mkfs_xfs >/dev/null 2>&1
>  if _scratch_mkfs_xfs_supports_concurrency -l >> $seqres.full 2>&1; then
> -	loop_mkfs_opts="-l concurrency=0"
> +	loop_mkfs_opts="-d concurrency=0 -l concurrency=0 -r concurrency=0"

/me notes that -lconcurrency is not compatible with -llogdev and the
loopdev is not formatted with SCRATCH_MKFS_OPTIONS, so this won't work
to disable the concurrency= mkfs options if fstests is being run with
SCRATCH_LOGDEV set.

--D

>  else
>  	loop_mkfs_opts=""
>  fi
> -- 
> 2.53.0
> 
> 

Re: [PATCH 2/2] xfs/216: disable all concurrency scaling

[Christoph Hellwig]

On Wed, Jun 24, 2026 at 10:44:04AM -0700, Darrick J. Wong wrote:
> On Fri, Jun 19, 2026 at 07:09:29AM +0200, Christoph Hellwig wrote:
> > This test currently disables log concurrency scaling, but even the
> > data device concurrency scaling can create mismatching output on
> > systems with a large CPU count.
> > 
> > Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> > Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> > ---
> >  tests/xfs/216 | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/tests/xfs/216 b/tests/xfs/216
> > index 1749647c11f7..ce8bb528410b 100755
> > --- a/tests/xfs/216
> > +++ b/tests/xfs/216
> > @@ -23,7 +23,7 @@ _cleanup()
> >  _require_scratch
> >  _scratch_mkfs_xfs >/dev/null 2>&1
> >  if _scratch_mkfs_xfs_supports_concurrency -l >> $seqres.full 2>&1; then
> > -	loop_mkfs_opts="-l concurrency=0"
> > +	loop_mkfs_opts="-d concurrency=0 -l concurrency=0 -r concurrency=0"
> 
> /me notes that -lconcurrency is not compatible with -llogdev and the
> loopdev is not formatted with SCRATCH_MKFS_OPTIONS, so this won't work
> to disable the concurrency= mkfs options if fstests is being run with
> SCRATCH_LOGDEV set.

Arrg.  I hate our option parsing mess.  Any good idea how we'd get
the desired result?  Unless there's something easy I'd be tempted to
leave it to the first person using an external log device and large
cpu counts..

Re: [PATCH 2/2] xfs/216: disable all concurrency scaling

[Darrick J. Wong]

On Thu, Jun 25, 2026 at 03:22:51PM +0200, Christoph Hellwig wrote:
> On Wed, Jun 24, 2026 at 10:44:04AM -0700, Darrick J. Wong wrote:
> > On Fri, Jun 19, 2026 at 07:09:29AM +0200, Christoph Hellwig wrote:
> > > This test currently disables log concurrency scaling, but even the
> > > data device concurrency scaling can create mismatching output on
> > > systems with a large CPU count.
> > > 
> > > Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> > > Signed-off-by: Christoph Hellwig <hch@lst.de>
> > > Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> > > ---
> > >  tests/xfs/216 | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/tests/xfs/216 b/tests/xfs/216
> > > index 1749647c11f7..ce8bb528410b 100755
> > > --- a/tests/xfs/216
> > > +++ b/tests/xfs/216
> > > @@ -23,7 +23,7 @@ _cleanup()
> > >  _require_scratch
> > >  _scratch_mkfs_xfs >/dev/null 2>&1
> > >  if _scratch_mkfs_xfs_supports_concurrency -l >> $seqres.full 2>&1; then
> > > -	loop_mkfs_opts="-l concurrency=0"
> > > +	loop_mkfs_opts="-d concurrency=0 -l concurrency=0 -r concurrency=0"
> > 
> > /me notes that -lconcurrency is not compatible with -llogdev and the
> > loopdev is not formatted with SCRATCH_MKFS_OPTIONS, so this won't work
> > to disable the concurrency= mkfs options if fstests is being run with
> > SCRATCH_LOGDEV set.
> 
> Arrg.  I hate our option parsing mess.  Any good idea how we'd get
> the desired result?  Unless there's something easy I'd be tempted to
> leave it to the first person using an external log device and large
> cpu counts..

Yeah, that's me. :)

I just sent my latest batch of random fixes:
https://lore.kernel.org/fstests/178240619625.1665857.3954516357764795627.stgit@frogsfrogsfrogs/

I don't know that it's necessary to add -dconcurrency=0 for xfs/216
after that (it seemed to work for me) but I don't have any objections to
adding more:

if _mkfs_xfs_supported $loop_mkfs_opts -l concurrency=0 $loop_dev &>> $seqres.full; then
	loop_mkfs_opts="$loop_mkfs_opts -l concurrency=0"
fi
if _mkfs_xfs_supported $loop_mkfs_opts -d concurrency=0 $loop_dev &>> $seqres.full; then
	loop_mkfs_opts="$loop_mkfs_opts -d concurrency=0"
fi

--D

Re: [PATCH 2/2] xfs/216: disable all concurrency scaling

[Christoph Hellwig]

I'll retract this patch in favour of the btrfs fix from Darrick.
We'll still need patch 1, though.