Messages in this thread | | | Date | Wed, 1 Oct 2008 15:09:40 -0700 | From | "Ray Lee" <> | Subject | Re: Regular system 'hiccups' with 2.6.25+ on amd64 machines |
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On Wed, Oct 1, 2008 at 2:51 PM, Marek Szuba <scriptkiddie@wp.pl> wrote: > Hello everyone, > > While I am not sure whether this is a bug or not, the phenomenon is > rather peculiar so I have decided to ask here. The problem is, upgrading > the kernel on any of my two AMD64 boxes from 2.6.24 to 2.6.25 or newer > causes both systems to get "hiccups", that it every half a second or so > they briefly freeze. Below you will find two examples of the problem: > > 1. On both systems, refreshing icons in the system tray takes much more > time than before: whereas with 2.6.24 the flicker of icons as they get > updated is barely noticeable, with 2.6.25+ you can see it quite clearly > and sometimes you can even see blank background of the tray app. > > 2. On the weaker of the two systems (Athlon64 3500+, 2 GB RAM, > nForce-based motherboard, on-board sound device supported by the > intel8x0 ALSA driver), one can hear audio playback (tested primarily > on a Shoutcast stream) stutter on a regular basis even with > buffering enabled. With 2.6.24 this never happened, even under heavy > system load. > > 3. I run an instance of Internet DJ Console (idjc), which used JACK, on > the stronger of the two systems (Athlon64 4000+, 2 GB RAM, nForce-based > motherboard, Sound Blaster Audigy 2 PCI card with ALSA driver emu10k1). > Up to and including 2.6.24 I've never had any problems with streaming > to the Icecast server I use, even under relatively heavy system load - > those few xruns, of just a few ms each, that did happen were removed by > buffering. However, under 2.6.25 and up I start getting xruns as soon > as idjc starts, even before I connect to the Icecast server or start > broadcasting anything! These look as follows: > > **** alsa_pcm: xrun of at least 1222893019070.464 msecs > > (the value is always the same) and appear more-or-less twice per > second. When I do connect to the server and begin streaming, the sound > as received by clients is audibly choppy when the system is otherwise > idle and becomes extremely distorted under load. The problem persists > after switching to an Icecast server running on the same machine, or indeed > if instead of running an independent media client I enable (in idjc) > listening to the stream before it gets sent to the server. > > > As I mentioned earlier, the problem affects all kernel versions I have > tried from 2.6.25 up to and including 2.6.26.5 - both vanilla versions > and with the grsecurity patch applied. Attached you will find my config > files for 2.6.24.7 and 2.6.26.5. Unfortunately I do not know whether the > problem affects other architectures than amd64. > > I would greatly appreciate it if you could look into the problem and > let me know what is wrong - i.e. whether this is a bug, an > unnecessarily-enabled feature, something that just needs a bit of > tuning and so on. If you need any more information regarding the issue, > my set-ups and so on, please don't hesitate to contact me (by > writing to my e-mail address - I'm not subscribed to LKML at present)! > > Yours sincerely, > -- > MS >
$ bzgrep -i group config.2.6.26.5.bz2 # CONFIG_CGROUPS is not set CONFIG_GROUP_SCHED=y CONFIG_FAIR_GROUP_SCHED=y # CONFIG_RT_GROUP_SCHED is not set # CONFIG_CGROUP_SCHED is not set
The group scheduler has (or at least had, prior to now) known fairness and interactivity issues. Please disable it and try again.
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