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Date: Sun, 30 Oct 2005 18:00:24 +0800
From: David Xu <davidxu@freebsd.org>
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Cc: Alexander Leidinger <Alexander@Leidinger.net>
Subject: Re: TSC instead of ACPI: powerd doesn't work anymore
	(to	be	expected?)
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David O'Brien wrote:

>>TSC is faster than any others, on many systems, so-called ACPI-fast
>>timer is really a slow chip,
>>    
>>
>
>Correct, but why is it felt the latency of the ACPI timer is an issue?
>Of course we all want things to as fast as possible, but is that just an
>abstract desire, or a real issue was run into?
>
>  
>
mysql benchmark - supersmack already told us this is an issue, this
is the reason why mysql runs slower on FreeBSD than on Linux:

ACPI-fast timecounter:

alona# super-smack ./select-key-local.smack 10 1000
Query Barrel Report for client smacker1
connect: max=4ms  min=3ms avg= 3ms from 10 clients
Query_type      num_queries     max_time        min_time        q_per_s
select_index    20000   1       0       7210.39

TSC timecounter:

alona# super-smack ./select-key-local.smack 10 1000
Query Barrel Report for client smacker1
connect: max=3ms  min=2ms avg= 2ms from 10 clients
Query_type      num_queries     max_time        min_time        q_per_s
select_index    20000   0       0       9301.19