Re: TCQ problems in 2.6.0-test1: the summary

From: David Ford (
Date: Mon Jul 21 2003 - 11:21:58 EST

> > 4) Using a tcq-enabled kernel with queue depth of 8 results in

>>massive filesystem corruption for me, verified under reiserfs, and xfs.
>>Elevator choice does not appear to matter, while queue depth is
>>important - I do not appear to get filesystem corruption with queue
>>depth of 32. Reiser refuses to mount with such a kernel, and runs
>>--fix-fixable at boot time. This is reproducible every time.
>This is really strange. The only difference between using 8 or 32 tags
>is when ide-disk stops attempting to queue. Are you getting any errors
>in dmesg when this happens? Reading the start io path for this, it looks
>correct to me. I'll have to try and reproduce when I get back.
On my laptop:

Here is the only thing that is similar on my system. When TCQ is
enabled, I have filesystem problems (minimal) every time I reboot and it
nearly always affects the same files every time. I too am using
reiserfs. I usually run reiserfsck and emerge the particular group of
files. For a while it was openssl libraries, now it's kde libraries.

Note, reiserfsck never indicates any problems were found or fixed but
the problems are none-the-less fixed. (reiser guys: reiserfsck
--fix-fixable always results in "--fix-fixable ignored")

Also note that there is never any indication ever that something is
wacky. Just out of the blue a file or files are corrupt and the bootup
result is the same every time.

(~) # hdparm -I /dev/hda |head -n10


ATA device, with non-removable media
        Model Number: IC25N030ATCS04-0
        Serial Number: CSL305DAGVK71A
        Firmware Revision: CA3OA72A

On one of my servers:

TCQ fscks it up bad. It ran for over a month on .73 with nary an issue
then all of a sudden it started barfing within hours of boot complaining

Jul 19 10:55:31 james hdc: invalidating tag queue (0 commands)
Jul 19 10:55:41 james ide_tcq_intr_timeout: timeout waiting for
completion interrupt

and further disk access causes D state. I upgraded this machine to
2.6.0-test1 and now it's having fits with apic or acpi but that's
another email. And a side note, if I have TCQ compiled in w/
2.6.0-test1, the kernel barfs a long 40+ function OOPS on bootup. It's
a 24/7 server so I haven't put a serial cable on it to capture the oops
yet :/

(~) # hdparm -I /dev/hdc


ATA device, with non-removable media
        Model Number: IBM-DPTA-372050
        Serial Number: JMYJMFZ1555
        Firmware Revision: P76OA30A

more if desired.

Other than this, I don't see any filesystem issues.


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This archive was generated by hypermail 2b29 : Wed Jul 23 2003 - 22:00:43 EST