Re: svn commit: r1387981 - /subversion/branches/10Gb/BRANCH-README

On Thu, Sep 20, 2012 at 9:22 PM, Branko Čibej <brane_at_wandisco.com> wrote:

> On 20.09.2012 13:41, stefan2_at_apache.org wrote:
> > +Bottlenecks to address:
> > +
> > +* frequent cancellation checks (intense OS interaction)
>
> I don't understand this part: since when do cancellation checks involve
> interaction with the OS? I thought the cancellation flag was an (atomic,
> volatile) thing that requires neither cpu-level atomic operations, nor
> higher-level locking.
>

It may not actually be "the OS" but the phenomenon is real.
check_for_error() in ra_svn/editorp.c calls apr_poll(), which in
turn calls select().

To make things worse, we buffer small output data like props
etc. but check for errors after each of them. So, more select()
calls then socket writes ...

My idea is to short-circuit the check until at least x amount
of data has been sent.

-- Stefan^2.

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