Messages in this thread | | | Date | Fri, 15 Feb 2002 11:07:26 -0800 | From | Andrew Morton <> | Subject | Re: fsync delays for a long time. |
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Simon Kirby wrote: > > Not sure if this is related, but I still can't get 2.4 or 2.5 kernels to > actually read and write at the same time during a large file copy between > two totally separate devices (eg: from hda1 to hdc1). "vmstat 1" shows > reads with no writing for about 6-8 seconds followed by writes with no > reading for about 5-6 seconds, repeat.
That's different.
It tends to be the case that when the dirty-data-generator hits a particular threshold, it blocks while we write out vast amounts of data. So the throughput is very lumpy.
It's probable that it can be tamed a bit by fiddling with the /proc/sys/vm/bdflush parameters.
> Is there a patch available that could fix this?
The -aa patches fiddle extensively with the bdflush thresholds and logic. There's stuff in there which might addresses this.
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