Messages in this thread | | | Subject | RE: [PATCH] idle using PNI monitor/mwait | Date | Wed, 9 Jul 2003 18:17:32 -0700 | From | "Saxena, Sunil" <> |
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Thermal advantages may be there and like "pause" they would be implementation specific.
Thanks Sunil
-----Original Message----- From: Zwane Mwaikambo [mailto:zwane@arm.linux.org.uk] Sent: Tuesday, July 08, 2003 11:42 PM To: Nakajima, Jun Cc: Linus Torvalds; linux-kernel@vger.kernel.org; Saxena, Sunil; Mallick, Asit K; Pallipadi, Venkatesh Subject: RE: [PATCH] idle using PNI monitor/mwait
On Tue, 8 Jul 2003, Nakajima, Jun wrote:
> That's right. If we have a lot of high-contention locks in the kernel, > we need to fix the code first, to get benefits for the other > architectures. > > "mwait" granularity (64-byte, for example) is given by the cpuid > instruction, and we did not use it because 1) it's unlikely that the > other fields of the task structure are modified when it's idle, 2) the > processor needs to check the flag after mwait anyway, to avoid waking up > with a false signal caused by other break events (i.e. mwait is a hint).
It could still be very handy for polling loops of the form;
while (!ready) __asm__ ("pause;");
Jun would there be any thermal advantages over using poll and pause ?
Thanks, Zwane -- function.linuxpower.ca - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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