Re: Patch 2.5.25: Ensure xtime_lock and timerlist_lock are on difft cachelines

From: Rusty Russell (rusty@rustcorp.com.au)
Date: Fri Jul 26 2002 - 01:24:51 EST

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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.
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