I think this is a libsysfs/iprutils issue due to a sysfs change in
recent kernels. Install sysfsutils 1.3.0, then grab the latest iprutils
package from
http://prdownloads.sourceforge.net/iprdd/iprutils-2.0.15.4-1.src.rpm?download.
Rebuild against libsysfs 1.3 with --target=ppc and upgrade the package.
Restart the following iprutils init.d services: iprinit, iprupdate,
iprdump and re-run your test.
Brian
Sonny Rao wrote:
Hi Brian,
I recently noticed a severe regression on certain
filesystems for a simple dd create test. The odd thing was that
filesystems which implemented the "writepages" aop along with
"writepage" aop (which all writable filesystems implement) didn't seem
to suffer nearly as much. So, I was thinking that maybe TCQ or
something isn't quite working correctly.
I have tried the same file creation test on non-local fibre storage
and don't see the degredation there, and we don't see it on x86 or
x86-64 either.
I noticed the problem in 2.6.13-rc6 but I tracked it down to a patch
that went into 2.6.12-rc5 which looks fairly benign. It was a merge
from Greg-KH's device driver tree into mainline:
http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=05d3794aa8bd3b2c9f7920a05003c331cdeb75c5
I have confirmed on multiple IPR machines that if I revert this patch
from 2.6.12-rc5, I see huge ( over 2x in some cases) improvements in
the dd file create test on the affected filesystems.
Do you have any idea why this would happen?
The only suspicious looking part to me is this one from
drivers/base/core.c
@@ -89,7 +87,6 @@ static void device_release(struct kobjec
static struct kobj_type ktype_device = {
.release = device_release,
.sysfs_ops = &dev_sysfs_ops,
- .default_attrs = dev_default_attrs,
};
But I really have no idea what is going on
I've attached the script I was using for the tests, the filesystems
which regress are ext3, xfs, and reiserfs. Just edit the variables at
the top for block device and mount-point for whatever machine you want
to run on.
Thanks,
Sonny Rao
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