Re: [PATCH] PM-Timer: doesn't use workaround if chipset is not buggy

From: bert hubert
Date: Sat Mar 25 2006 - 06:57:36 EST


> This patch adds blacklist of buggy chip, and if chip is not buggy,
> this uses fast normal version instead of slow workaround version.

I can confirm that this patch solves the problem I originally complained
about.

Timings of 10,000,000 gettimeofday calls on my pentium 4 3GHz (which I won
at OLS, ha!):

tsc
---
real 0m2.504s
user 0m0.700s
sys 0m1.804s

2.6.16-mainline
---------------
real 0m36.973s
user 0m1.440s
sys 0m34.130s

2.6.16-ogawa
------------
real 0m13.697s
user 0m1.712s
sys 0m11.117s

For reference, baseline 2.6.16 on my Athlon64 3200+
---------------------------------------------------
real 0m1.994s
user 0m0.990s
sys 0m0.990s

I'm still going to recommend all 'power' pdns_recursor users on single CPU
and not using frequency scaling to boot with clock=tsc - saves
2.2usec/packet. Or run on an opteron of course.

Thanks for the work everybody!

--
http://www.PowerDNS.com Open source, database driven DNS Software
http://netherlabs.nl Open and Closed source services
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