From: Linus Torvalds <torvalds@osdl.org>
To: Paul Venezia <pvenezia@jpj.net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: ext3 performance inconsistencies, 2.4/2.6
Date: Tue, 4 Nov 2003 11:36:55 -0800 (PST) [thread overview]
Message-ID: <Pine.LNX.4.44.0311041130480.20373-100000@home.osdl.org> (raw)
In-Reply-To: <1067973024.23788.24.camel@d8000>
On Tue, 4 Nov 2003, Paul Venezia 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?
Which makes me suspect that either the libc does something different
depending on kernel version, _or_ 2.4.22 returns a different st_blksize
thing, causing stdio to use a different blocking size.
Have you tried stracing the "per char" parts of the benchmark to see what
the system call patterns are? That should show both effects.
Linus
next prev parent reply other threads:[~2003-11-04 19:37 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-11-04 19:10 ext3 performance inconsistencies, 2.4/2.6 Paul Venezia
2003-11-04 19:36 ` Linus Torvalds [this message]
2003-11-04 20:20 ` Bill Rugolsky Jr.
2003-11-04 20:30 ` Linus Torvalds
2003-11-04 21:07 ` Paul Venezia
2003-11-04 21:28 ` Bill Rugolsky Jr.
2003-11-04 21:40 ` Linus Torvalds
2003-11-04 22:00 ` Ulrich Drepper
2003-11-04 22:31 ` Linus Torvalds
2003-11-04 23:48 ` Ulrich Drepper
2003-11-04 23:56 ` Linus Torvalds
2003-11-05 0:58 ` jlnance
2003-11-05 7:08 ` Jakub Jelinek
2003-11-04 22:19 ` Bill Rugolsky Jr.
2003-11-04 22:26 ` Bill Rugolsky Jr.
2003-11-05 7:14 ` Jakub Jelinek
2003-11-04 21:39 ` Bill Rugolsky Jr.
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