Bug 415091

Summary: hald-addon-storage polling every 2 seconds should not cause 20 wakeups / second from libata
Product: [Fedora] Fedora Reporter: Oliver Henshaw <oliver.henshaw>
Component: halAssignee: David Zeuthen <davidz>
Status: CLOSED DUPLICATE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: low Docs Contact:
Priority: low    
Version: 8CC: mclasen
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2007-12-07 16:09:42 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Attachments:
Description Flags
strace -tt of both hald-addon-storage processes with empty drives
none
strace -tt of both hald-addon-storage processes with locked drives none

Description Oliver Henshaw 2007-12-07 00:32:51 UTC 
Description of problem:
Powertop reveals 20 interrupts from libata per second when there is no hard disk
activity. It may be relevant that there are two (ide) optical drives on this
system. I understand that hald-addon-storage polls the cd/dvd drives every
couple of seconds, but this still seems like too many.

Some data points:
* Killing hald-addon-storage from powertop causes libata wakeups to drop to
near-zero (0.2/second over 15 seconds).
* Inserting an audio cd in each drive and then quitting kscd so that both drives
are locked results in only around 2 interrupts/second from libata.
* As an aside, this is better than kernel 2.6.23.1-49 which had typically 40
wakeups/second and around 3 wakeups / second even after killing hald-addon-storage.

Based on the attached strace, below, I suspect that hald-addon-storage is
polling the two optical drives in alternate seconds. Something like bug #204969
comment #1 may help synchronize the times that the two optical drives are
polled. This would still leave the problem of hald-addon-storage causing 20
wakeups every time it polls is - whether this is due to some inefficiency or
can't be helped, I don't know.

Version-Release number of selected component (if applicable):
hal-0.5.10-1
kernel-2.6.23.8-63
Comment 1 Oliver Henshaw 2007-12-07 00:46:13 UTC 
Created attachment 280311 [details]
strace -tt of both hald-addon-storage processes with empty drives

The strace output I've attached seems to actually have both drives being polled
in the same second, unlike an earlier test I did not record, and contrary to my
claim above.  Still, there may be a way to better synchronize the polling or
make it more efficient in terms of interrupts.
Comment 2 Oliver Henshaw 2007-12-07 00:47:10 UTC 
Created attachment 280331 [details]
 strace -tt of both hald-addon-storage processes with locked drives
Comment 3 David Zeuthen 2007-12-07 16:09:42 UTC 

*** This bug has been marked as a duplicate of 204969 ***