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Date: Tue, 28 Feb 2012 12:21:53 +0200
From: Andriy Gapon <avg@FreeBSD.org>
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To: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>
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Cc: freebsd-hackers@FreeBSD.org, Grzegorz Kulewski <grzegorz@kulewski.pl>
Subject: Re: improving VM - questions
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on 28/02/2012 11:43 Wojciech Puchar said the following:
>>> +++ swap_pager.c        2012-02-25 13:19:51.000000000 +0100
>>> @@ -119,7 +119,7 @@
>>>  * The 32-page limit is due to the radix code (kern/subr_blist.c).
>>>  */
>>> #ifndef MAX_PAGEOUT_CLUSTER
>>> -#define MAX_PAGEOUT_CLUSTER 16
>>> +#define MAX_PAGEOUT_CLUSTER 256
>>> #endif
>> [snip]
>>> but swap_pager.c patch seems not to work. i observe 64kB pageouts, no more.
>>>
>>> what is wrong in it?
>>
>> Could there be a problem because of what the MAX_PAGEOUT_CLUSTER comment says?
> 
> right. but still 32 pages is 128kB, but i see 64kB I/Os in systat/vmstat

Right, but the comment says to not define MAX_PAGEOUT_CLUSTER to a value greater
than 32, but you did that.  So all bets could be off unless you examined the
code and know exactly what should happen in this case.


-- 
Andriy Gapon