[REPORT] 2.6.21 vs. 2.6.21-sd046 vs. 2.6.21-CFSv7

[REPORT] 2.6.21 vs. 2.6.21-sd046 vs. 2.6.21-CFSv7

[Bill Davidsen]

System: Intel 6600 Core2duo, 2GB RAM, X nice 0 for all tests, display 
using i945G framebuffer

Test: playing a 'toon with mplayer while kernel build -j20 running.

Tuning: not yet, all scheduler parameters were default

Result: base 2.6.21 showed some pauses and after the pause the sound got 
louder for a short time (<500ms). With sd-0.46 the playback had many 
glitches and finally just stopped with the display looping on a small 
number of frames and no sound. The skips were repeatable, the hang was 
only two of five runs, I didn't let them go until the make finished 
(todo list) but killed the mplayer after 10-15 sec. No glitches observed 
with cfsv7, I thought I saw one but repeating with granularity set to 
500000 and then with no make running convinced me that it's just a 
crappy piece of animation at that point.

I ran glxgears, again sd-0.46 had frequent pauses and uneven fps 
reported. Stock 2.6.21 had a visible pause when the frame rate was 
output, otherwise minimal pauses. CFSv7 appeared smooth at about 250 fps.

All tests gave acceptable typing echo, it seems that X is getting enough 
time at that load to echo without major issues.

I will be doing tests with server load later this week, have to add disk 
for the database.

Hope this initial report is useful, I may be able to update ctxbench 
later today and try that.

-- 
Bill Davidsen <davidsen@tmr.com>
  "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot

Re: [REPORT] 2.6.21 vs. 2.6.21-sd046 vs. 2.6.21-CFSv7

[Bill Davidsen]

Bill Davidsen wrote:
> System: Intel 6600 Core2duo, 2GB RAM, X nice 0 for all tests, display 
> using i945G framebuffer
> 
> Test: playing a 'toon with mplayer while kernel build -j20 running.
> 
> Tuning: not yet, all scheduler parameters were default
> 
> Result: base 2.6.21 showed some pauses and after the pause the sound got 
> louder for a short time (<500ms). With sd-0.46 the playback had many 
> glitches and finally just stopped with the display looping on a small 
> number of frames and no sound. The skips were repeatable, the hang was 
> only two of five runs, I didn't let them go until the make finished 
> (todo list) but killed the mplayer after 10-15 sec. No glitches observed 
> with cfsv7, I thought I saw one but repeating with granularity set to 
> 500000 and then with no make running convinced me that it's just a 
> crappy piece of animation at that point.
> 
> I ran glxgears, again sd-0.46 had frequent pauses and uneven fps 
> reported. Stock 2.6.21 had a visible pause when the frame rate was 
> output, otherwise minimal pauses. CFSv7 appeared smooth at about 250 fps.
> 
> All tests gave acceptable typing echo, it seems that X is getting enough 
> time at that load to echo without major issues.
> 
> I will be doing tests with server load later this week, have to add disk 
> for the database.
> 
> Hope this initial report is useful, I may be able to update ctxbench 
> later today and try that.
> 
Followup: I reran with sd-0.46, setting rr_interval to 40, and then 5 
(default was 16). Neither appeared to give a useful video playback. I 
did try setting the make to nice 10, and that made the playback 
perfectly smooth, as well as response to skip forward and volume change 
happening when the key was pressed instead of eventually.

I also tried raising the nice of X to -10, that made things better on 
display, but I winder if it will let X run ahead of the nice-0 raid threads.

Is this my hardware or is there a really odd behavior here? The sd seems 
to be too fair to cope well with this realistic load, and expecting 
users to nice things is probably morally correct but unrealistic.

Re: [REPORT] 2.6.21 vs. 2.6.21-sd046 vs. 2.6.21-CFSv7

[Bill Huey]

On Mon, Apr 30, 2007 at 03:58:45PM -0400, Bill Davidsen wrote:
> Followup: I reran with sd-0.46, setting rr_interval to 40, and then 5 
> (default was 16). Neither appeared to give a useful video playback. I 
> did try setting the make to nice 10, and that made the playback 
> perfectly smooth, as well as response to skip forward and volume change 
> happening when the key was pressed instead of eventually.
> 
> I also tried raising the nice of X to -10, that made things better on 
> display, but I winder if it will let X run ahead of the nice-0 raid threads.
> 
> Is this my hardware or is there a really odd behavior here? The sd seems 
> to be too fair to cope well with this realistic load, and expecting 
> users to nice things is probably morally correct but unrealistic.

People have been reporting very good performance with regards to OpenGL
applications under SD. What is your video driver ? NVidia proprietary ?

OpenGL, X and direct frame buffer access (mplayer and friends) tend not
to interact each other which can result in very different scheduling
characteristics between them.

[please CC the relevant people for their own benefit]

bill

Re: [REPORT] 2.6.21 vs. 2.6.21-sd046 vs. 2.6.21-CFSv7

[Bill Davidsen]

Bill Huey (hui) wrote:
> On Mon, Apr 30, 2007 at 03:58:45PM -0400, Bill Davidsen wrote:
>   
>> Followup: I reran with sd-0.46, setting rr_interval to 40, and then 5 
>> (default was 16). Neither appeared to give a useful video playback. I 
>> did try setting the make to nice 10, and that made the playback 
>> perfectly smooth, as well as response to skip forward and volume change 
>> happening when the key was pressed instead of eventually.
>>
>> I also tried raising the nice of X to -10, that made things better on 
>> display, but I winder if it will let X run ahead of the nice-0 raid threads.
>>
>> Is this my hardware or is there a really odd behavior here? The sd seems 
>> to be too fair to cope well with this realistic load, and expecting 
>> users to nice things is probably morally correct but unrealistic.
>>     
>
> People have been reporting very good performance with regards to OpenGL
> applications under SD. What is your video driver ? NVidia proprietary ?
>
>   
My original post I was following gave my config, built-in graphics using 
945G framebuffer. This is a server, I'm not a gamer. The only fancy 
graphics I have are on a system with no on board video at all, I picked 
up a moderately high-end Radeon card to drop in. And to give you an idea 
of what a gamer I am, that uses the vesafb driver ;-)
> OpenGL, X and direct frame buffer access (mplayer and friends) tend not
> to interact each other which can result in very different scheduling
> characteristics between them.
>   

-- 
bill davidsen <davidsen@tmr.com>
  CTO TMR Associates, Inc
  Doing interesting things with small computers since 1979

Re: [REPORT] 2.6.21 vs. 2.6.21-sd046 vs. 2.6.21-CFSv7

[Con Kolivas]

On Tuesday 01 May 2007 05:29, Bill Davidsen wrote:
> System: Intel 6600 Core2duo, 2GB RAM, X nice 0 for all tests, display
> using i945G framebuffer

Bill thanks for testing.
>
> Test: playing a 'toon with mplayer while kernel build -j20 running.

Umm I don't think make -j20 is a realistic load on 2 cores. Not only does it 
raise your load to 20 but your I/O bandwidth will even be struggling. If 
video playback was to be smooth at that size a load it would suggest some 
serious unfairness. I'm not just pushing the fairness barrow here; I mean it 
would need to be really really unfair unless your combined X and video 
playback cpu combined added up to less than 1/20th of your total cpu power 
(which is possible but I kinda doubt it). Do you really use make -j20 to 
build regularly?

> Tuning: not yet, all scheduler parameters were default
>
> Result: base 2.6.21 showed some pauses and after the pause the sound got
> louder for a short time (<500ms). With sd-0.46 the playback had many
> glitches and finally just stopped with the display looping on a small
> number of frames and no sound. The skips were repeatable, the hang was
> only two of five runs, I didn't let them go until the make finished
> (todo list) but killed the mplayer after 10-15 sec. No glitches observed
> with cfsv7, I thought I saw one but repeating with granularity set to
> 500000 and then with no make running convinced me that it's just a
> crappy piece of animation at that point.

I did notice on your followup email that nice +10 of the 20 makes fixed the 
playback which sounds pretty good.

> I ran glxgears, again sd-0.46 had frequent pauses and uneven fps
> reported. Stock 2.6.21 had a visible pause when the frame rate was
> output, otherwise minimal pauses. CFSv7 appeared smooth at about 250 fps.

I assume you mean glxgears when you're running make -j20 again here.

> All tests gave acceptable typing echo, it seems that X is getting enough
> time at that load to echo without major issues.

That's nice; shows stability under load.

> I will be doing tests with server load later this week, have to add disk
> for the database.

Great.

> Hope this initial report is useful, I may be able to update ctxbench
> later today and try that.

Also good.

-- 
-ck

Re: [REPORT] 2.6.21 vs. 2.6.21-sd046 vs. 2.6.21-CFSv7

[Bill Davidsen]

Con Kolivas wrote:
> On Tuesday 01 May 2007 05:29, Bill Davidsen wrote:
>   
>> System: Intel 6600 Core2duo, 2GB RAM, X nice 0 for all tests, display
>> using i945G framebuffer
>>     
>
> Bill thanks for testing.
>   
>> Test: playing a 'toon with mplayer while kernel build -j20 running.
>>     
>
> Umm I don't think make -j20 is a realistic load on 2 cores. Not only does it 
> raise your load to 20 but your I/O bandwidth will even be struggling. If 
> video playback was to be smooth at that size a load it would suggest some 
> serious unfairness. I'm not just pushing the fairness barrow here; I mean it 
> would need to be really really unfair unless your combined X and video 
> playback cpu combined added up to less than 1/20th of your total cpu power 
> (which is possible but I kinda doubt it). Do you really use make -j20 to 
> build regularly?
>
>   
Yes, this is a compile and file server, I frequently build a raft of 
kernels when a security patch comes out. There doesn't seem to be an i/o 
issue, with 2GB RAM and RAID5 over a SATA array I have enough, but 
honestly the disk activity is minimal, even with a single drive.
>> Tuning: not yet, all scheduler parameters were default
>>
>> Result: base 2.6.21 showed some pauses and after the pause the sound got
>> louder for a short time (<500ms). With sd-0.46 the playback had many
>> glitches and finally just stopped with the display looping on a small
>> number of frames and no sound. The skips were repeatable, the hang was
>> only two of five runs, I didn't let them go until the make finished
>> (todo list) but killed the mplayer after 10-15 sec. No glitches observed
>> with cfsv7, I thought I saw one but repeating with granularity set to
>> 500000 and then with no make running convinced me that it's just a
>> crappy piece of animation at that point.
>>     
>
> I did notice on your followup email that nice +10 of the 20 makes fixed the 
> playback which sounds pretty good.
>
>   
Yes, I can get around the load doing that.
>> I ran glxgears, again sd-0.46 had frequent pauses and uneven fps
>> reported. Stock 2.6.21 had a visible pause when the frame rate was
>> output, otherwise minimal pauses. CFSv7 appeared smooth at about 250 fps.
>>     
>
> I assume you mean glxgears when you're running make -j20 again here.
>   
Of course. ;-)

-- 
bill davidsen <davidsen@tmr.com>
  CTO TMR Associates, Inc
  Doing interesting things with small computers since 1979