From: Andrew Morton <andrewm@uow.edu.au>
To: "linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: it gets slower
Date: Thu, 15 Mar 2001 00:26:06 +1100 [thread overview]
Message-ID: <3AAF716E.1B776E31@uow.edu.au> (raw)
After doing a huge amount of disk I/O the other day I noted
that a subsequent full kernel build took *ages*. I haven't
been able to reproduce the full extent of this, but..
Doing a build after boot takes 320 seconds. After
copying two kernel trees and diffing them, an identical
full build takes 336 seconds. Profiling each build says:
Before:
c01120b0 do_page_fault 1453 1.2440
c0271a00 __generic_copy_to_user 1741 29.0167
c0122c6c do_wp_page 1895 2.9609
c012da88 rmqueue 2245 3.7922
c0271a3c __generic_copy_from_user 3593 59.8833
c01260f0 file_read_actor 4490 41.5741
c0123388 do_anonymous_page 11121 89.6855
c01071c0 default_idle 21741 418.0962
00000000 total 71684 0.0469
After:
c0271a00 __generic_copy_to_user 1696 28.2667
c0122c6c do_wp_page 1865 2.9141
c012da88 rmqueue 2226 3.7601
c0271a3c __generic_copy_from_user 3584 59.7333
c01260f0 file_read_actor 4529 41.9352
c0123388 do_anonymous_page 11324 91.3226
c01071c0 default_idle 34807 669.3654
00000000 total 90069 0.0590
This is a 1kHz profile, so we've spent an extra 13 seconds in
default_idle. Doing I/O, presumably. 256 meg dual Celeron.
Why?
Also, we spent 12 seconds in do_anonymous_page and do_wp_page
madly memsetting. Has anyone tried prezeroing some pages in
default_idle(), so they're ready to go?
Yes, I know it'll probably be cachely disadvantageous,
but has anyone actually tried and measured it?
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux.eu.org/Linux-MM/
reply other threads:[~2001-03-14 13:24 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=3AAF716E.1B776E31@uow.edu.au \
--to=andrewm@uow.edu.au \
--cc=linux-mm@kvack.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox