Bug 204725

Summary: hplip wakes up every half second
Product: [Fedora] Fedora Reporter: Arjan van de Ven <arjan>
Component: hplipAssignee: Tim Waugh <twaugh>
Status: CLOSED RAWHIDE QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: rawhide   
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Fixed In Version: 1.6.7-4 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2006-10-03 11:34:49 EDT Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---
Bug Depends On:    
Bug Blocks: 150223, 204948    

Description Arjan van de Ven 2006-08-31 04:40:50 EDT
Description of problem:

hplip has a loop that wakes up every half second.
We're working on making the kernel tickless for power management reasons, which
of course is no gain if various userspace apps keep waking the processor up all
the time. In runlevel 3, hpssd is one of the bigger wakers. (half a second may
sound nitpicky, but if there are 2 dozen places doing it it's still a mess).

As far as I can see from the code this timeout is just used for a select()
timeout, and any event that comes in on the sockets earlier will wake the app up
anyway, so half a second is way overkill. In fact it's not quite clear to me why
the select() can't just be unlimited, but ok. The patch below as proof of
concept turns the 0.5s into 5 seconds... but I'd love to see it even longer...

--- hpssd.py~   2006-08-31 10:21:35.000000000 +0200
+++ hpssd.py    2006-08-31 10:21:35.000000000 +0200
@@ -1474,7 +1474,7 @@
         log.debug("Starting async loop...")
-            loop(timeout=0.5)
+            loop(timeout=5.0)
         except KeyboardInterrupt:
             log.warn("Ctrl-C hit, exiting...")
         except Exception:
Comment 1 Tim Waugh 2006-12-21 07:39:33 EST
This patch is now accepted upstream, but they didn't respond to 'why does it
need to time out at all?'; I'll keep trying with it.