Date: Sat, 04 Feb 2006 08:46:32 +0100 From: Ivan Voras <ivoras@fer.hr> To: Andrew Gallatin <gallatin@cs.duke.edu> Cc: current@freebsd.org Subject: Re: machdep.cpu_idle_hlt and SMP perf? Message-ID: <43E45BD8.7070708@fer.hr> In-Reply-To: <17379.56708.421007.613310@grasshopper.cs.duke.edu> References: <17379.56708.421007.613310@grasshopper.cs.duke.edu>
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Andrew Gallatin wrote:
> Why dooes machdep.cpu_idle_hlt=1 drop my 10GbE network rx
> performance by a considerable amount (7.5Gbs -> 5.5Gbs)?
For what it's worth, here are results of unixbench's "context1"
benchmark on an old P3 SMP with and without cpu_idle_hlt (6-stable):
x hlt=0
+ hlt=1
+--------------------------------------------------------------------------+
| + ++ + + x xx x x|
||_______M___A____________| |____M__A_______| |
+--------------------------------------------------------------------------+
N Min Max Median Avg Stddev
x 5 346203 355234 347787 349229.8 3549.1559
+ 5 322710 337269 325631 327663.8 5622.9044
Difference at 95.0% confidence
-21566 +/- 6857.28
-6.1753% +/- 1.96354%
(Student's t, pooled s = 4701.78)
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