Re: Strange write starvation on 2.6.17 (and other) kernels

[Neil Brown]

On Thursday August 17, miquels@xxxxxxxxxx wrote:
> In article <44E0A69C.5030103@xxxxxxxxxx>,
> Andrzej Szymanski  <szymans@xxxxxxxxxx> wrote:
> >I've encountered a strange problem - if an application is sequentially 
> >writing a large file on a busy machine, a single write() of 64KB may 
> >take even 30 seconds. But if I do fsync() after each write() the maximum 
> >time of write()+fsync() is about 0.5 second (the overall performance is, 
> >of course, degraded).
> 
> I'm seeing something similar.

Can you report the contents of /proc/meminfo before, during, and after
the long pause?
I'm particularly interested in MemTotal, Dirty, and Writeback, but the
others are of interest too.

Thanks,
NeilBrown
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