Re: ReiserFS slow, need help diagnosing

[Juergen Starek <quiterigorouslyfilteredusenetaccount@gmx.de>]

Vladimir V. Saveliev schrieb:
> On Mon, 2006-06-05 at 15:11 +0200, Juergen Starek wrote:
>
>> I have noticed that if I put my ~ on a ReiserFS partition, Pan (GNOME's
>> newsreader) starts very slowly, [...]
> 
> Probably Pan is stat(2)-ing whole cache. Can you please try to find out
> what Pan is doing on start? Strace(1) may help.

You're right, I straced Pan's start process and after initialization, it
seems to call stat64 on every message in its cache. This is a snippet of
the trace, produced on an ext3 filesystem (line length exceeds 80 chars): 

==========
stat64("/home/jstarek/.pan/gmane", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
stat64("/home/jstarek/.pan/Standard", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0

stat64("/home/jstarek/.pan/messages/cache", {st_mode=S_IFDIR|0755, st_size=1032192, ...}) = 0
open("/home/jstarek/.pan/messages/cache", O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_DIRECTORY) = 6
fstat64(6, {st_mode=S_IFDIR|0755, st_size=1032192, ...}) = 0
fcntl64(6, F_SETFD, FD_CLOEXEC)         = 0
getdents64(6, /* 62 entries */, 4096)   = 4096
stat64("/home/jstarek/.pan/messages/cache/42b4e3b2$0$1128$9b4e6d93@newsread4.arcor-online.net.msg", {st_mode=S_IFREG|0644, st_size=1426, ...}) = 0
time(NULL)                              = 1149517138
==========

The last two calls of this trace snippet are then repeated for all files
in the cache.

> If Pan is doing millions of stats for files from cache - that explains
> why it starts slowly when cache is stored on reiserfs.

Could you please explain this? An URL with the explanation is fine, too --
I just don't have experience with file systems...

Thanks,

  Jürgen