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Message-ID: <468E8B71.90602@Yahoo.com>
Date: Fri, 06 Jul 2007 14:35:29 -0400
From: Jan Wieck <JanWieck@Yahoo.com>
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To: Heikki Linnakangas <heikki@enterprisedb.com>
CC: Peter Eisentraut <peter_e@gmx.net>, pgsql-hackers@postgresql.org
Subject: Re: usleep feature for pgbench
References: <468D42B3.4010701@Yahoo.com> <200707061644.57878.peter_e@gmx.net>
	<468E7AC3.3040501@Yahoo.com> <468E7CAB.9070802@enterprisedb.com>
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On 7/6/2007 1:32 PM, Heikki Linnakangas wrote:
> Jan Wieck wrote:
>> On 7/6/2007 10:44 AM, Peter Eisentraut wrote:
>>> Am Donnerstag, 5. Juli 2007 21:12 schrieb Jan Wieck:
>>>> To test some changes in Slony I needed a
>>>>
>>>>      \usleep [microseconds|:variable]
>>>>
>>>> in pgbench's scripting language to be able to have hundreds of
>>>> concurrent running transactions without totally swamping the system. I
>>>> was wondering if anyone would object to permanently adding this to the
>>>> pgbench code?
>>>
>>> Or maybe a \sleep command that takes units, if it's not too much work.
>>>
>> 
>> You mean as a second, optional argument? Good idea.
>> 
>>   us = microseconds
>>   ms = milliseconds
>>   s  = seconds (default)
>> 
>>   \sleep {value|:variable} [us|ms|s]
>> 
>> Is that okay with everyone?
> 
> I won't object, but is it really worth the trouble?
> 
> Can you do microsecond precision sleeps, and on what platforms? How much 
> overhead is there? IIRC, on Linux the minimum time you can sleep depends 
> on CONFIG_HZ, and the default was 10 ms until recently.
> 

It is what you tell select(2) in the struct timeval. Why limit it to 
some arbitrary precision?


Jan

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