[Jfs-discussion] performance

[Sean N. <sne...@zo...>]

Hi,

I've been playing with JFS this past day or so, and I am observing a
performance problem.  I am using a patched kernel (version 14a of Rik
van Riel's rmap VM), so this may be implicated somehow.

When I do a build of the LNX-BBC (http://www.lnx-bbc.org/) I get a
build time of about 75 minutes on an ext3 volume, and about 84 minutes
on a JFS volume.  I'm using stock ext3 and JFS version 1.10, on Linux
2.4.19 plus the rmap patch.

Here's some data, from "time make install":

On ext3:

real    76m37.636s
user    38m59.370s
sys     18m34.210s

On JFS:

real    84m13.123s
user    39m3.020s
sys     18m49.810s

The machine in question is an SMP box with 1.13GHz P-III, 256M of RAM
and IDE disks.  I use ccache (http//ccache.samba.org/) to do these
builds, and see almost identical hit/miss statistics for each run.  I
believe that, due to ccache, the build becomes fairly I/O-bound.
Judging by fact that the wall-clock time shows the only big variation,
I'm guessing (wildly, with no proof) that this may be something to do
with how JFS schedules I/O.

If there is any other information you'd like me to gather, please holler.

-- 
 /                          |
[|] Sean Neakums            |  Questions are a burden to others;
[|] <sne...@zo...>     |      answers a prison for oneself.
 \                          |