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From: David Xu <davidxu@freebsd.org>
To: Julian Elischer <julian@elischer.org>
Date: Sat, 20 May 2006 11:12:21 +0800
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Cc: freebsd-threads@freebsd.org
Subject: Re: optimize msleep with PCATCH flag
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On Saturday 20 May 2006 09:49, Julian Elischer wrote:
> looks like you need to do a lot more samples to get a better error
> value.. (8 may not be enough)

Is 40 enough ? this time, the system runs in single user mode, so
any noise is eliminated.

x plain_PCATCH.st
+ PCATCH_optimized.st
+--------------------------------------------------------------------------+
|      +                                                                   |
|      +    +                                                              |
|      +    +                                                              |
|      +    +                  x x                                         |
|   +  ++++ +                  x xx                                        |
|  ++++++++++ +          xx x xxxxx                      x                 |
|+ +++++++++++++ +    x xxx+xxxxxxxxx xxx   x x   xxx    xx   x x         x|
|   |____A____|          |_______M____A___________|                        |
+--------------------------------------------------------------------------+
    N           Min           Max        Median           Avg        Stddev
x  40         31199         38404       32691.5     33376.775     1740.5576
+  40         28245         31794       29300.5       29380.8     649.64192
Difference at 95.0% confidence
	-3995.98 +/- 584.857
	-11.9723% +/- 1.75229%
	(Student's t, pooled s = 1313.69)