lkml.org 
[lkml]   [1998]   [Jun]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
Subjectunlink aggressively robs resources
I've noticed this with 2.1.84, .86, and .103 kernels.  When you unlink
large files on an ext2 disk, the machine becomes extremely choppy. Not
only is disk bandwidth stolen almost completely for that operation, but
the cpu also seems to be at a loss. The systems I'm using all have 512Mb
of RAM, they're dual cpu, some are ppro 200s, some are p-ii 266s, some are
p-ii 400s. They all have buslogic scsi, with ultrawide disks.

I don't really have numbers to show this. But it's pretty easy to
reproduce these sorts of situations. For example, create a couple 512Mb
files and delete them at the same time, while trying to accomplish
anything else (like a compile in the background).

Other similar nonsense can be created with stuff like:

#!/bin/sh
while dd if=/dev/zero of=foo.$$ bs=4096 count=16384 1>/dev/null 2>&1 \
&& cat foo.$$ >/dev/null; do
:
done

Run a few of those at the same time. They will saturate the disk, and
anything else trying to use the disk will have no hope.

I know this last example is abusive. But I don't think deleting large
files is abusive.

I can guess what's going on... but I wouldn't mind hearing it from folks
more familiar with the code.

Dean


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu

\
 
 \ /
  Last update: 2005-03-22 13:42    [from the cache]
©2003-2011 Jasper Spaans