Kolivas Pushes New Kernel Responsiveness Patches

[energyman]

if it is all about disk - why does a big copy make the mouse laggy? Hello? Mouse? Surely must be all the data that the mouse has to read from the disk all the time.
Why is switching from X to vt or back goddamn slow when accessing a damaged disk at the same time? Why is waiting for ide timeouts making your nose bleed in anger?

http://forums.gentoo.org/viewtopic-t-482731-postdays-0-postorder-asc-start-0.html

http://forums.gentoo.org/viewtopic-t-793263.html

those are 40 pages of suffering and trying stuff. Without much results.
It is not even a new problem. This goes back to 2.2.10 (the kernel I started with) and never became better...

[kraftman]

if it is all about disk - why does a big copy make the mouse laggy? Hello? Mouse? Surely must be all the data that the mouse has to read from the disk all the time.
Why is switching from X to vt or back goddamn slow when accessing a damaged disk at the same time? Why is waiting for ide timeouts making your nose bleed in anger?

Because some people are complaining about CFS not about CFQ

[arjan_intel]

if it is all about disk - why does a big copy make the mouse laggy? .

That's likely neither the process scheduler or the disk scheduler, but the VM subsystem.... it threw out the code pages for the mouse X code.. and now it needs to be read back from disk.

[energyman]

that would explain an initial lag - but not the following stuttering. Also why should the VM discard code pages with tons of memory available?
And seriously, discarding code of running programms sounds really really wrong.

[illissius]

I don't think it's either a CPU scheduler nor a disk scheduler issue. If it were a problem with the disk scheduler, it would only affect other processes also accessing the disk, which plainly isn't the case. I also don't think it's the CPU scheduler, because I'd think in that case with a dual core CPU it could just put the disk stuff on one core and let the other stuff keep running on the other core. But that's not what happens. Even with two cores shit gets lagged up badly when doing disk-intensive stuff.

I also don't think it's the VM subsystem... granted, the VM subsystem has its own pathologies (how long will it be before we can finally get it to never, ever favor file cache over application data?), but this happens even when there's plenty of physical memory free.

As I said, I suspect it's something structural. But I'm not a kernel developer, so other than speculating "it's probably not X, because...", I can't really say.

[arjan_intel]

As I said, I suspect it's something structural. But I'm not a kernel developer, so other than speculating "it's probably not X, because...", I can't really say.

if you can get timechart set up (part of the perf program), you can do

perf timechart record sleep 10
perf timechart

the first command will do a 10 second recording of the activity in your system
the second command will turn the recording into a svg image.

with that, it's maybe possible to figure out what is going on, assuming the actual stuttering can be captured (if it's very reproducable, it should be)

[energyman]

ok, I copied one 4.4gb iso from one md raid5 partition to another - /mnt/date to /var. system is on a SSD.
At first it was ok. Then the mouse hanged twice will doing that perf command.

It did so a few more times after those 10 seconds. Every couple of seconds the mouse hangs.

I have to admit, it got better. Not too long ago it would have been horrible. - 8gb ram helped a lot.

And now I have a huuuuge svg. I am uploading it right now at rapidshare, if someone is interessted.

[Naib]

Well been running 2.6.33-ck1 for the last 6h.
Done some gentoo update with no noticable change

QL however ran smoother!!!
No noticable difference in HoN

so seems good will be sticking with it

[pejakm]

Well been running 2.6.33-ck1 for the last 6h.
Done some gentoo update with no noticable change

QL however ran smoother!!!
No noticable difference in HoN

so seems good will be sticking with it

Zen kernel have the ck patchset included. (Btw, I'm using zen kernel since year ago, works great.)

[Yfrwlf]

It will probably never be merged. The majority of the kernel devs agreed that there won't be more than one CPU scheduler in the kernel.

If one is better for desktop use, and the other for server use, maybe both should be? One that did best under both situations would be ideal though of course.