Re: fsync delays for a long time.

Simon Kirby
2002-02-15T17:25:11Z

On Thu, Feb 14, 2002 at 12:51:14PM -0800, Andrew Morton wrote:

> Alan Cox wrote:
> >
> > > run my gdbm application and bonnie test on the same device.
> > > When gdbm comes to the point when it calls fsync it delays for a long
> > > time.
> >
> > fsync on a very large file is very slow on the 2.2 kernels
>
> This could very well be due to request allocation starvation.
> fsync is sleeping in __get_request_wait() while bonnie keeps
> on stealing all the requests.
>
> Recall that patch you dropped on Tuesday? :)

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.

Is there a patch available that could fix this?

Simon-

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