gentoo-sources-2.6.24 slower ?

Moonboots · Apprentice Joined: 02 Dec 2006 Posts: 164

While encoding a x264 video using mencoder, i noticed that 2.6.24 appears to be between 7-10% slower compared to 2.6.23-r6.
During encoding there was a greater fluctuation and a lower total utilization of both cpu's in the latest kernel.
Anyone else noticed a similar effect ?

aTan · Posted: Sat Jan 26, 2008 6:52 pm Post subject:

it is also buggy as hell (for me). i've turned on ticklessness and hires timer and it hung up system within several minutes with IO overload. it is possible that ntfs-3g causes it, because it started to be unresponsive after copying to a ntfs partition. but before becoming totally dead it started to send 's' letter constantly to every active application. who knows what is it... I will try it w/o ticklessness and hires timer, but i've been waiting for it on amd64 for a long time.

mantoo · Posted: Sat Jan 26, 2008 6:55 pm Post subject:

may thats in relation with the cfs-scheduler which i read was "updated an optimized"...

well, it's to expect that it therefore should run faster... but maybe because of granting a fast and low-latency desktop by the the new scheduler, there might be a loss of speed in some context...

excuse my english....

8086 · n00b Joined: 12 Dec 2007 Posts: 52

I've switched to 2.6.24 and I'm not experiencing any slow-downs. How did you configure your new kernel?

Moonboots · Apprentice Joined: 02 Dec 2006 Posts: 164

Using my old config as a guide, although verifying correct options are 'ticked' by menuconfig.
Perhaps it's just a mencoder/x264 problem ?

Skrot · Posted: Sat Jan 26, 2008 11:01 pm Post subject:

In the short testing I've done with the .24 kernel, things overall felt a bit nicer (I don't think I could justify this if I had to), but when I play World of Warcraft in Wine the game drops a whole bunch of frames around every 10 seconds or there abouts. It doesn't exactly 'pause', but it goes low enough frame rate as to appear so. This was infuriating so I went back to .23.

I've looked through the kernel config and changed a few options to see if it was one of the 'policy' type ones that I selected to play around with, but I nothing I changed helped this. There still could for sure be something that I missed when I checked the config again, but it seems as though the scheduler changed in some way that made WoW through Wine worse.
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energyman76b · Advocate Joined: 26 Mar 2003 Posts: 2048 Location: Germany

have you activated that 'group support' scheduler option?

because that can cause some 'virtual' slowdown.
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Skrot · Posted: Sat Jan 26, 2008 11:59 pm Post subject:

Hm no. I had that on at first (mainly because it was new and shiny and I like to play around with things I know nothing about), and I suspected that it might be the cause of my problems, but I deactivated that and the problem was still there.

I think I'll get a fresh copy of the .config from my .23 kernel then run oldconfig again and not enable those things. I'll see how it goes.
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toralf · Posted: Sun Jan 27, 2008 11:22 am Post subject:

Try to unset kernel option CONFIG_FAIR_GROUP_SCHED .

Moonboots · Apprentice Joined: 02 Dec 2006 Posts: 164

I tried enabling/disabling these newer kernel features, without success in my case with respect to mencoder.
As a infrequent app and the increased encoding time amounting to only 15mins, it's not that important.
Other than that , the new kernel works fine.