Re: [rfc][patch] queued spinlocks (i386)

From: Davide Libenzi
Date: Thu Mar 29 2007 - 22:46:01 EST


On Fri, 30 Mar 2007, Nick Piggin wrote:

> > I slightly modified it to use cycles:
> >
> > http://www.xmailserver.org/qspins.c
>
> Slightly more than slightly ;)
>
> You want to have a delay _outside_ the critical section as well, for
> multi-thread tests, otherwise the releasing CPU often just retakes
> the lock (in the unqueued lock case). As I said, most kernel code
> should _not_ be dropping and retaking locks.

Yeah. ATM it mostly does double-takes.



- Davide


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