From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Adrian Cox <adrian@humboldt.co.uk>
Cc: linuxppc-dev@ozlabs.org, Paul Mackerras <paulus@samba.org>
Subject: Re: Worst case performance of up()
Date: Wed, 06 Dec 2006 09:00:02 +1100 [thread overview]
Message-ID: <1165356002.5469.16.camel@localhost.localdomain> (raw)
In-Reply-To: <1165263946.29784.13.camel@localhost.localdomain>
> > If ppc_md.power_save is NULL, then the idle loop does not touch the flag
> > word of the idle thread, and everything works.
>
> Good to know, there might be other cases of performance issues due to
> touching that flag in a loop...
More specifically... that means we have the same performance problem on
SMP PowerMacs (dual G4s & Xserve G4s)... on those machines, there's a
firmware property telling us not to use NAP mode and we do so by
clearing powersave_nap.
Paul, do you reckon the best solution here is to clear ppc_md.power_save
when detecting an SMP powermac ? (Or the flush-on-lock property)
Ben.
next prev parent reply other threads:[~2006-12-05 21:59 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-24 16:21 Worst case performance of up() Adrian Cox
2006-11-24 20:45 ` Benjamin Herrenschmidt
2006-11-27 21:02 ` Adrian Cox
2006-12-02 10:35 ` Adrian Cox
2006-12-02 11:15 ` Benjamin Herrenschmidt
2006-12-02 11:54 ` Adrian Cox
2006-12-02 20:52 ` Benjamin Herrenschmidt
2006-12-04 13:43 ` Adrian Cox
2006-12-04 20:25 ` Benjamin Herrenschmidt
2006-12-05 22:00 ` Benjamin Herrenschmidt [this message]
2006-12-08 2:33 ` Paul Mackerras
2006-12-08 3:10 ` Benjamin Herrenschmidt
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