Increasing MAXPHYS

Poul-Henning Kamp phk at
Mon Mar 22 08:23:46 UTC 2010

In message <4BA633A0.2090108 at>, Andriy Gapon writes:
>on 21/03/2010 16:05 Alexander Motin said the following:
>> Ivan Voras wrote:
>>> Hmm, it looks like it could be easy to spawn more g_* threads (and,
>>> barring specific class behaviour, it has a fair chance of working out of
>>> the box) but the incoming queue will need to also be broken up for
>>> greater effect.
>> According to "notes", looks there is a good chance to obtain races, as
>> some places expect only one up and one down thread.
>I haven't given any deep thought to this issue, but I remember us discussing
>them over beer :-)

The easiest way to obtain more parallelism, is to divide the mesh into
multiple independent meshes.

This will do you no good if you have five disks in a RAID-5 config, but
if you have two disks each mounted on its own filesystem, you can run
a g_up & g_down for each of them.

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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