Gluster users - Oct 2009 - change fuse max_read= mount option from 128k to something bigger?

Hi

Are there any caveats to changing the max_read fuse mount option that's
hardcoded into xlators/mount/fuse/src/fuse-bridge.c to something other 
than 128k?

On my client test system, cat /proc/mounts shows:

fusectl /sys/fs/fuse/connections fusectl rw,relatime 0 0
10.10.10.11 /storage fuse.glusterfs
rw,relatime,user_id=0,group_id=0,default_permissions,allow_other,max_read=131072
0 0

This is a deb (lenny) based x86_64 system, but the kernel is vanilla 
2.6.31.1 although the library is the default apt based 
libfuse-dev_2.7.4-1.1 one.

Thanks.

Mohan

The returns for the effort of increasing the fuse channel size is
hardly anything. Though you will see a nice increase in performance
when block size is increased, because of the reduction of context
switches, there will be a peak after which increasing the block size
further has no benefits. Since a transaction involves memcpy of the
buffers, the larger block sizes start becoming less friendly with your
hardware memory caches and start working against your
performance.
>From our tests 128KB (the default maximum) is very ideal.
Avati

On Sun, Oct 11, 2009 at 6:55 AM,  <mki-glusterfs at mozone.net>
wrote:
> Hi
>
> Are there any caveats to changing the max_read fuse mount option that's
> hardcoded into xlators/mount/fuse/src/fuse-bridge.c to something other
> than 128k?
>
> On my client test system, cat /proc/mounts shows:
>
> fusectl /sys/fs/fuse/connections fusectl rw,relatime 0 0
> 10.10.10.11 /storage fuse.glusterfs
rw,relatime,user_id=0,group_id=0,default_permissions,allow_other,max_read=131072
0 0
>
> This is a deb (lenny) based x86_64 system, but the kernel is vanilla
> 2.6.31.1 although the library is the default apt based
> libfuse-dev_2.7.4-1.1 one.
>
> Thanks.
>
> Mohan
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