[OpenAFS-devel] performance issues with 1.4.8 and above

[Felix Frank]

Hi,

I've been busy doing a couple of stress tests lately. A disturbing finding 
is that the 1.4.7 fileserver achieves nearly 25% higher data throughput 
than 1.4.8 and 1.4.10 respectively.

My test server is amd64_rhel50 with kernel 2.6.18-92.1.22.el5 and uses two 
bonded NICs.
All test clients are amd64_rhel50 as well, 2.6.18-128.1.6.el5, using 64MB 
memcaches.

The test comprised a simultaneous "dd if=/afs/... of=/dev/null".
To 5 and more clients, a 1.4.7 server will consistently serve ~160MB/s, 
whereas higher versions yield <130MB/s.

All tests were performed using client version 1.4.7 (with RxOSD patch) and
1.4.10 (with and without RxOSD patch) respectively. Server versions tested 
were 1.4.7, 1.4.8 and 1.4.10 (in addition to some with RxOSD patch).

The server was built with --enable-bitmap-later 
--enable-bos-restricted-mode --enable-bos-new-config --enable-fast-restart 
--enable-supergroups --enable-largefile-fileserver --enable-transarc-paths 
--with-krb5-conf
It's invoked with -L -p 50 -rxpck 300 -s 1000 -l 1000 -cb 65535 -b 250 -syslog

Can anyone confirm this?

Regards
Felix