Re: Linux 2.6.29

Pavel Machek
2009-04-03T12:39:33Z

Hi!

> > I'm utterly and screamingly bored of this "Blame userspace" attitude.
>
> I'm not blaming userspace. I'm blaming ourselves, for implementing an
> attractive nuisance, and not realizing that we had implemented an
> attractive nuisance; which years later, is also responsible for these
> latency problems, both with and without fsync() ---- *and* which have
> also traied people into believing that fsync() is always expensive,
> and must be avoided at all costs --- which had not previously been
> true!

Well... fsync is quite expensive. If your disk is down, it costs 3+
and 3J+. If your disk is up, it will only take 20msec+.

OTOH the rename trick on ext3 costs approximately nothing...

Imagine those desktops where they want windows layout
preserved. Having 30 second old layout is acceptable, loosing layout
altogether is not. If you add fsync to the window manager, user will
see those 3seconds+ delays, unless window manager gets multithreaded.

Pavel
--
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