[19629] in Athena Bugs
stat() slowness on Linux Laptop running 9.0.1[34]
daemon@ATHENA.MIT.EDU (Derek Atkins)
Thu Aug 16 13:09:38 2001
To: bugs@MIT.EDU
Cc: aurora@MIT.EDU
From: Derek Atkins <warlord@MIT.EDU>
Date: 16 Aug 2001 13:09:34 -0400
Message-ID: <sjmlmkk3p9t.fsf@rcn.ihtfp.org>
Hi,
I just installed Heather's new laptop with Linux-Athena. I started
with the SIPB Installer and 8.4.x, then updated to 9.0.14 (and have
since downgraded to 9.0.13 -- I'll explain in a bit). The problem is
that 'attach' takes a VERY long time to complete. I've interrupted
the process using gdb's 'attach' functionality and every time it's
been hanging in 'lstat64()' or some other stat variant.
I've got a desktop machine also running 9.0.13 (hense why I downgraded
the laptop) which doesn't have this problem. Both machines are
sitting behind the same T-1, and that that should be the limiting path
between here and MIT. I've tried using two different network cards in
the laptop (one wired, one wireless) and I have the same problem.
Considering the laptop has a faster process, faster bus, and more
memory than the desktop, I find this very strange.
Another example of the problem: From the shell, if I type something
like "cd /afs/sipb/pro<TAB>" it will hang for a LONG period of time
before it completes.
Note that this only happens the first time. Once the information is
in the AFS stat cache, completions happen very quickly. Similarly for
logins, once the information is in the stat cache, it works fine.
However, if I reboot the machine I get the slowness again. (This
tells me it has to do with the stat cache, which is ephemeral, and not
the data cache, with is persistent across reboots). So, this problem
is completely reproducible on my part.
What I don't understand is why the laptop is having problems and the
desktop is not. If I reboot the desktop I do see a _bit_ of slowness
logging in, but not nearly as drastic as the laptop.
I've saved a tcpdump output from the login process if anything thinks
this would be useful. You can find it in /mit/warlord/login-slowness/
along with other information that might be useful later in this
discussion. Considering the 'fs setcrypt' is on, I'm not sure how
useful it will actually be, but it will at least show how long it
takes to login. The dump was started just before I logged in, and
stopped just as I logged out (which I did as soon as my login
completed).
Thanks,
-derek
--
Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
Member, MIT Student Information Processing Board (SIPB)
URL: http://web.mit.edu/warlord/ PP-ASEL-IA N1NWH
warlord@MIT.EDU PGP key available
