Re: [PATCH RFC] smt nice introduces significant lock contention

From: Con Kolivas
Date: Fri Jun 02 2006 - 04:17:09 EST


On Friday 02 June 2006 17:53, Nick Piggin wrote:
> This is a small micro-optimisation / cleanup we can do after
> smtnice gets converted to use trylocks. Might result in a little
> less cacheline footprint in some cases.

It's only dependent_sleeper that is being converted in these patches. The
wake_sleeping_dependent component still locks all runqueues and needs to
succeed in order to ensure a task doesn't keep sleeping indefinitely. That
one doesn't get called from schedule() so is far less expensive. This means I
don't think we can change that cpu based locking order which I believe was
introduce to prevent a deadlock (?DaveJ disovered it iirc).

--
-ck
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/