Messages in this thread | | | From | Ricardo Galli <> | Subject | Re: Report: 2.4.18 very high latencies (with lowlat. and pre-empt patches) | Date | Fri, 5 Apr 2002 12:16:05 +0200 |
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On 05/04/02 00:29, Andrew Morton wrote: > Ricardo Galli wrote: > > Hi all (second try), > > Linux becomes somehow unusable when I edited sound files and also > > during NFS copy. I've noticed the same effects also during i/o loads, for > > example when closing kmail after I deleted some messages. > > It would help if you could come up with a simple test case > which exhibits this problem - some sequence of steps which > is reproducible by others, and which has repeatable effects.
To test computer A, which has installed Linux 2.4.18 + all low latency patches.
1. Put ten (10) to twenty (20) files of 64-80 MB each in computer B. For example in /tmp/test.
2. Mount in B a disk in A via NFS in, for example, /mnt/A
3. In B, run the following command: cp /tmp/test/* /mnt/A
4. Check in A how you mouse freezes.
If you are a Debian Sid user, don't do any dist-upgrade for a couple of days and then try it. You will see the same mouse freezes when apt-get is installing/configuring packages.
> Is your I/O system performing properly? Try running > > hdparm -t /dev/hdaX > > where /dev/hdaX refers to your root filesystem. You > should get 15-30 megabytes per second.
Yes.
# hdparm -t /dev/hda
/dev/hda: Timing buffered disk reads: 64 MB in 2.32 seconds = 27.59 MB/sec
> You also report that your PPC-based laptop has processes > unexpectedly terminating when the machine is under VM > pressure. You should check your kernel logs (usually > /var/log/messages) to see if the process was killed > due to an out-of-memory condition. If it's not that, > and if it's not due to application bugs then the ppc > kernel may be dropping modified- or dirty-bits in its > PTEs, which is rather unlikely.
The PPC hasn't any problem at all, it was the NFS server who has killed kmail. There were not logged messages at all.
Regards,
-- ricardo "I just stopped using Windows and now you tell me to use Mirrors?" - said Aunt Tillie, just before downloading 2.5.3 kernel. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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