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From: Rusty Russell <rusty@rustcorp.com.au>
To: Ravikiran G Thirumalai <kiran@in.ibm.com>
Cc: linux-kernel@vger.kernel.org, torvalds@transmeta.com
Subject: Re: Patch 2.5.25: Ensure xtime_lock and timerlist_lock are on difft cachelines
Date: Fri, 26 Jul 2002 16:24:51 +1000	[thread overview]
Message-ID: <20020726063124.5114E45D6@lists.samba.org> (raw)
In-Reply-To: Your message of "Thu, 25 Jul 2002 20:45:12 +0530." <20020725204512.E3594@in.ibm.com>

In message <20020725204512.E3594@in.ibm.com> you write:
> I've noticed that xtime_lock and timerlist_lock ends up on the same
> cacheline  all the time (atleaset on x86).  Not a good thing for
> loads with high xxx_timer and do_gettimeofday counts I guess (networking etc)
..

Better might be to use the x86-64 trick of using sequence counters
around do_gettimeofday, and avoid the xtime lock altogether.  That
will improve gettimeofday performance as well.  Or you could try
changing xtime lock to a brlock.

FYI: as policy, I don't take optimization patches without
measurements.  I'm just not that smart.

Thanks,
Rusty.
--
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.

  reply	other threads:[~2002-07-26  6:27 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-07-25 15:15 Patch 2.5.25: Ensure xtime_lock and timerlist_lock are on difft cachelines Ravikiran G Thirumalai
2002-07-26  6:24 ` Rusty Russell [this message]
2002-07-26  7:26   ` Kiran
2002-07-26  7:56     ` Rusty Russell
2002-07-26  9:23       ` Kiran
2002-07-27  4:17         ` Rusty Russell

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