Date: Fri, 12 Oct 2001 14:51:10 -0700 From: "Jay Rossiter" <jrossiter@symantec.com> To: freebsd-hackers@freebsd.org Subject: Severe I/O Problems Message-ID: <OF771AB257.5E1F2BC6-ON88256AE3.0077DC3F@symantec.com>
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Someone on -questions recommended that I forward this over here for
you guys to look at. (I'm not subbed to this list)
There appear to be a lot of changes that went into the filesystem and I/O
code between 4.3 and 4.4. A little over a week ago I upgraded my 4.3 box
to 4.4-STABLE and immediately I started having I/O slowdown. I do
development and QA on a program that is very I/O bound, but the changes
between 4.3 and 4.4 aren't small enough that I can ignore them.
A few statistics:
BSD, P4 1.4GHz, ATA100 drives
- Normal test run on 4.3 was taking ~3 hours.
- Normal test run on 4.4 is taking 15-16 hours.
P3-800, ATA66 drives, SuSE Linux 7.1:
- Normal test run takes ~4.5 hours.
UltraSparc 10, Solaris 8, ATA66 drives:
- Normal test run takes ~6 hours.
As you can see, this jump was just phenomenal.
I can run these tests on a custom 'ramdrive' and the test run takes 1.5
hours on BSD. ~4 on Solaris, ~2.5 on Linux.
Even the RS/6000 I test AIX 4.3 with doesn't take this long, though I don't
have statistics for it.
It appears that the app gets stuck switching between the getblk and biowr
states in top and ps, and very rarely does it take more than 5% of the CPU.
On all other OS's, and even on 4.3, this app was pegging the CPU while it
did its work.
Basically.. this all comes down to "What the hell is going on here?!" and
"Are there plans to fix it and did anyone even know there was a problem?"
---
Jay Rossiter 503-614-7917
QA Engineer, Test Lead
Symantec Corp.
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