Bug 512616 - squid wakes up the CPU when doing nothing
Summary: squid wakes up the CPU when doing nothing
Keywords:
Status: CLOSED NEXTRELEASE
Alias: None
Product: Fedora
Classification: Fedora
Component: squid
Version: 11
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Jiri Skala
QA Contact: Fedora Extras Quality Assurance
URL: http://www.squid-cache.org/bugs/show_...
Whiteboard:
Depends On:
Blocks: wakeup
TreeView+ depends on / blocked
 
Reported: 2009-07-19 20:57 UTC by Edwin ten Brink
Modified: 2014-11-09 22:31 UTC (History)
6 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2009-07-22 07:17:24 UTC


Attachments (Terms of Use)

Description Edwin ten Brink 2009-07-19 20:57:35 UTC
Description of problem:
Even without any connected clients, squid wakes up the CPU 100 times per second according to powertop. This does not seem necessary.


Version-Release number of selected component (if applicable):
$ rpm -q squid
squid-3.0.STABLE15-2.fc11.i586

Comment 1 David Rees 2009-07-20 18:00:26 UTC
Confirmed here, also affects F10 since it has the same version of squid.  Powertop reports this:

  12.3% (100.8)             squid : __mod_timer (process_timeout)

Stracing squid shows this going on 100 times a second:

epoll_wait(6, {}, 16384, 10)            = 0

Comment 2 Henrik Nordström 2009-07-20 19:56:58 UTC
Upstream are aware of this. Don't remember right now why it needed to do this other than that it's a workaround for a timing race and that it is not likely to be fixed in 3.0.

3.1 will behave better and will be available in F-12.

Comment 3 Edwin ten Brink 2009-07-21 19:38:10 UTC
(In reply to comment #2)
Found your original posting on squid-users mailing list in October 2008:
http://www.squid-cache.org/mail-archive/squid-users/200810/0158.html

(In reply to comment #1)
David, you seem to be right about the polling:
http://www.squid-cache.org/mail-archive/squid-users/200810/0148.html

Comment 4 Henrik Nordström 2009-07-21 20:02:26 UTC
The polling is a red herring (just an effect, not the cause), the issue is elsewhere, with the polling just plastering over it..

Linked to upstream bug report (closed).

Comment 5 Edwin ten Brink 2009-07-22 07:17:24 UTC
(In reply to comment #4)
> Linked to upstream bug report (closed).  

Ok, thanks. Let's close this one for now then with CLOSED - NEXTRELEASE (squid 3.1) as it appears to have been resolved indeed from the bug report at http://www.squid-cache.org/bugs/show_bug.cgi?id=2011


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