Re: ext3 performance inconsistencies, 2.4/2.6
From: Bill Rugolsky Jr.
Date: Tue Nov 04 2003 - 15:21:47 EST
On Tue, Nov 04, 2003 at 11:36:55AM -0800, Linus Torvalds wrote:
> > I've been running bonnie++ filesystems testing on an IBM x335 server
> > recently. This box uses the MPT RAID controller, but I've disabled the
> > RAID and am addressing the disks individually. I'm getting wildly
> > different results between 2.4.20-20-9 (RedHat mod), 2.4.22 (stock), and
> > 2.6.0-test9.
> Interesting. The 2.4.22 sequential "per char" results are totally out of
> line with anything else.
> The thing is, the overhead for the per-char stuff really should be almost
> all in user space unless I'm mistaken. It's just using getch/putch, no?
Unless bonnie++ is using the _unlocked() variants, it might be an issue of
the mutex overhead from NPTL v. LinuxThreads. Red Hat 9 has its share
of NPTL bugs.
It is probably worth rerunning the tests with LD_ASSUME_KERNEL=2.4.1 on
the Red Hat kernel.
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