improving VM - questions

[Artem Belevich]

On Tue, Feb 28, 2012 at 1:06 PM, Wojciech Puchar
<wojtek at wojtek.tensor.gdynia.pl> wrote:
>>>> 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.
>>
>> I suspect it might be DFLTPHYS that splits disk i/o into 64K blocks on
>> the driver level.
> can i increase DFLTPHYS as well as i did with MAXPHYS without problems?

Sorry, I don't have definitive answer to that.

This old post has some related info:
http://lists.freebsd.org/pipermail/freebsd-performance/2008-February/003311.html

Even older thread on freebsd-arch also described some concerns:
http://lists.freebsd.org/pipermail/freebsd-arch/2004-January/001590.html

I don't know whether the stuff above still applies to FreeBSD as it is now:

--Artem