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wazoo42
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Joined: 13 Apr 2004
Posts: 165
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 Posted: Tue Aug 18, 2009 8:12 pm Post subject: |
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| Jens Axboe's patch (post 397 in the link MageSlayer gave above) worked wonders for my amd64 install (dual core opteron) with vanilla 2.6.30.4. I'll work on getting some concrete numbers, hopefully they'll backup the improved responsiveness I see in KDE4. |
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devsk
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Joined: 24 Oct 2003
Posts: 3003
Location: Bay Area, CA
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| Posted: Tue Aug 18, 2009 8:27 pm Post subject: |
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| wazoo42 wrote: | | Jens Axboe's patch (post 397 in the link MageSlayer gave above) worked wonders for my amd64 install (dual core opteron) with vanilla 2.6.30.4. I'll work on getting some concrete numbers, hopefully they'll backup the improved responsiveness I see in KDE4. |
That's interesting! Are you using the patch with NCQ or without. Can you post the output of:
| Code: | | cat /sys/block/*/queue/nr_requests |
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MageSlayer
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Joined: 26 Jul 2007
Posts: 253
Location: Ukraine
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| Posted: Tue Aug 18, 2009 8:27 pm Post subject: |
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| Yes. It would be great if you could provide some interbench numbers. |
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wazoo42
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Joined: 13 Apr 2004
Posts: 165
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| Posted: Wed Aug 19, 2009 12:32 am Post subject: |
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It appears I'm using NCQ and the CFQ i/o scheduler.
| Code: | benjfitz linux # cat /sys/block/*/queue/nr_requests
128
128
128
128
128
128
128
128
benjfitz linux # cat /sys/block/sda/queue/scheduler
noop anticipatory deadline [cfq]
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devsk
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Joined: 24 Oct 2003
Posts: 3003
Location: Bay Area, CA
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| Posted: Wed Aug 19, 2009 12:55 am Post subject: |
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| wazoo42 wrote: | It appears I'm using NCQ and the CFQ i/o scheduler.
| Code: | benjfitz linux # cat /sys/block/*/queue/nr_requests
128
128
128
128
128
128
128
128
benjfitz linux # cat /sys/block/sda/queue/scheduler
noop anticipatory deadline [cfq]
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That's in contrast with what other people are seeing. hmmm... |
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3Towers
n00b
Joined: 27 Mar 2004
Posts: 8
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| Posted: Sun Aug 23, 2009 3:34 pm Post subject: |
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I have some more for you to test. For quite some time I had the same problems (unresponsive UI during IO operations and an almost completely freezed system when I was trying to rip a DVD with read errors). I tried several options already discussed in this thread (including the kernel ncq patch) with no success. Today I built a completely new kernel with the following options changed:
- disabled SMT (HyperThreading support) as my Q6700 doen't has HT
- enabled preemptile RCU
- enabled low latency desktop (forced preemption)
- disabled the IDE layer (only compiled libata SATA/PATA drivers)
additionally I swtched SATA mode in my BIOS to AHCI (IDE mode before) and set the RTC to 64bit.
With these settings all my problems are gone now! Only drawback: I'm not able to boot up Windowx XP with these BIOS settings if I need it again. *g*
When I have some more time I will try to figure out which option is responsible for this success and post it here.
Hope this can help some of you!  |
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energyman76b
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Joined: 26 Mar 2003
Posts: 2048
Location: Germany
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| Posted: Sun Aug 23, 2009 5:28 pm Post subject: |
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disable smt and ahci probably 
I don't have forced preemption nor rcu preemption and I don't suffer from long lags anymore. For a long time.
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kernelOfTruth
Watchman
Joined: 20 Dec 2005
Posts: 6111
Location: Vienna, Austria; Germany; hello world :)
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energyman76b
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Joined: 26 Mar 2003
Posts: 2048
Location: Germany
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| Posted: Sun Aug 23, 2009 8:03 pm Post subject: |
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| kernelOfTruth wrote: | | energyman76b wrote: | disable smt and ahci probably
I don't have forced preemption nor rcu preemption and I don't suffer from long lags anymore. For a long time. |
I got to test that with smt, thanks !
you don't need ahci anyways with your SCSI disks |
my superfast scsi disks are in my other box
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luispa
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Joined: 17 Mar 2006
Posts: 359
Location: España
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| Posted: Wed Aug 26, 2009 7:20 pm Post subject: |
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| wrc1944 wrote: | For those having this problem, especially if they have SATA drives, it would probably be worth a shot to try the deadline scheduler instead of cfq.
Everything I've read over the last year or so seems to indicate there is still an I/O problem with cfq on some systems, and also that generally with SATA drives deadline is often a better scheduler that cfq. Kernel >=2.6.30-rc4 seemed to improve it somewhat (as mentioned), but I'm still sticking with deadline myself until I'm convinced this is really fixed with cfq.
You need to enable support in your kernel (probably already has it, but check your .config file). If not, you'll need to recompile your kernel and enable deadline, but if it does already have it, just append your grub kernel line with
and reboot.
If it makes a difference great, but if not, just remove the append. |
wrc1944, thanks for the update. I spend some time with .30-rc4 but still suffering the issue I mentioned...
| luispa wrote: | @fangorn
Thanks for the information, as I said here is the result with 2.6.29: no problem, back to normal behaviour. I'm not suffering problems with I/O now. Obviously I cant add any value here, but my experience. 2.6.28: Ok, 2.6.30: I/O issue, 2.6.29: Ok.
Luis |
I'm going to try with your suggestion (deadline) and report back.
Luis |
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luispa
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Joined: 17 Mar 2006
Posts: 359
Location: España
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| Posted: Thu Aug 27, 2009 10:44 am Post subject: |
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| luispa wrote: |
I'm going to try with your suggestion (deadline) and report back.
Luis |
My report:
I've noticed now with .30 & deadline the system is more responsive but still seeing that disk writtes (syncing) are somehow delayed meaning sporadic reponsiveness, so in general I feel that the system is more reliable with .29.
With interbench didn't notice the difference. I've run it under runlevel 3 though, maybe I should run it under runlevel 1 as recommended.
Here is the output:
| Code: |
bolica interbench-0.30 # cat 2.6.29-gentoo-r5.log
Using 805133 loops per ms, running every load for 30 seconds
Benchmarking kernel 2.6.29-gentoo-r5 at datestamp 200908270935
--- Benchmarking simulated cpu of Audio in the presence of simulated ---
Load Latency +/- SD (ms) Max Latency % Desired CPU % Deadlines Met
None 0.013 +/- 0.088 1.93 100 100
Video 0.006 +/- 0.00695 0.015 100 100
X 0.01 +/- 0.061 1.47 100 100
Burn 0.022 +/- 0.261 5.79 100 100
Write 0.01 +/- 0.0375 0.733 100 100
Read 0.012 +/- 0.0677 1.64 100 100
Compile 0.111 +/- 0.983 16.6 100 100
Memload 0.021 +/- 0.088 1.52 100 100
--- Benchmarking simulated cpu of Video in the presence of simulated ---
Load Latency +/- SD (ms) Max Latency % Desired CPU % Deadlines Met
None 0.007 +/- 0.0205 0.809 100 100
X 0.015 +/- 0.138 3.45 100 100
Burn 0.016 +/- 0.152 4.17 100 100
Write 0.007 +/- 0.0153 0.481 100 100
Read 0.008 +/- 0.0144 0.406 100 100
Compile 0.023 +/- 0.357 10.9 100 100
Memload 0.017 +/- 0.027 0.668 100 100
--- Benchmarking simulated cpu of X in the presence of simulated ---
Load Latency +/- SD (ms) Max Latency % Desired CPU % Deadlines Met
None 0 +/- 0.00111 0.013 100 100
Video 0 +/- 0.000812 0.01 100 100
Burn 0.533 +/- 2.57 18 86.2 84.4
Write 0 +/- 0.00153 0.017 100 100
Read 0 +/- 0.0014 0.018 100 100
Compile 0.446 +/- 2.16 14 92.6 89.7
Memload 0 +/- 0.00165 0.018 100 100
--- Benchmarking simulated cpu of Gaming in the presence of simulated ---
Load Latency +/- SD (ms) Max Latency % Desired CPU
None 0 +/- 0 0 100
Video 0 +/- 0 0 100
X 0 +/- 0 0 100
Burn 1.35 +/- 4.43 19.7 98.7
Write 0 +/- 0 0 100
Read 0 +/- 0 0 100
Compile 4.89 +/- 8.49 34.1 95.3
Memload 0 +/- 0 0 100
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| Code: | bolica interbench-0.30 # cat 2.6.30-gentoo-r4.log
Using 805133 loops per ms, running every load for 30 seconds
Benchmarking kernel 2.6.30-gentoo-r4 at datestamp 200908271023
--- Benchmarking simulated cpu of Audio in the presence of simulated ---
Load Latency +/- SD (ms) Max Latency % Desired CPU % Deadlines Met
None 0.007 +/- 0.00727 0.015 100 100
Video 0.005 +/- 0.00515 0.011 100 100
X 0.006 +/- 0.00629 0.012 100 100
Burn 0.015 +/- 0.107 1.93 100 100
Write 0.008 +/- 0.00859 0.017 100 100
Read 0.008 +/- 0.00939 0.098 100 100
Compile 0.005 +/- 0.0054 0.014 100 100
Memload 0.021 +/- 0.122 2.45 100 100
--- Benchmarking simulated cpu of Video in the presence of simulated ---
Load Latency +/- SD (ms) Max Latency % Desired CPU % Deadlines Met
None 0.005 +/- 0.00553 0.015 100 100
X 0.005 +/- 0.00572 0.019 100 100
Burn 0.021 +/- 0.227 5.66 100 100
Write 0.006 +/- 0.00943 0.24 100 100
Read 0.006 +/- 0.00627 0.017 100 100
Compile 0.277 +/- 2.62 35.3 99.8 99
Memload 0.016 +/- 0.0319 0.719 100 100
--- Benchmarking simulated cpu of X in the presence of simulated ---
Load Latency +/- SD (ms) Max Latency % Desired CPU % Deadlines Met
None 0 +/- 0.000983 0.012 100 100
Video 0 +/- 0.000592 0.008 100 100
Burn 0.903 +/- 3.25 14 89 84.6
Write 0 +/- 0.00117 0.012 100 100
Read 0 +/- 0.00119 0.017 100 100
Compile 1.04 +/- 4 28 85.6 81
Memload 0 +/- 0.00156 0.021 100 100
--- Benchmarking simulated cpu of Gaming in the presence of simulated ---
Load Latency +/- SD (ms) Max Latency % Desired CPU
None 0 +/- 0 0 100
Video 0 +/- 0 0 100
X 0 +/- 0 0 100
Burn 1.38 +/- 4.24 14.3 98.6
Write 0 +/- 0 0 100
Read 0 +/- 0 0 100
Compile 3.35 +/- 7.49 34.4 96.8
Memload 0 +/- 0 0 100
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Thanks,
Luis |
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sidamos
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Joined: 16 Dec 2007
Posts: 246
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| Posted: Fri Sep 04, 2009 9:10 am Post subject: |
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| I have the same problem with AMD64x2 5400+ (running Gentoo 32 bit) and PATA disks. Also, they started with 2.6.30, AFAIK. I have low latency desktop on. I have tried cfq and anticipatory scheduler. However, IMHO this should not be relevant if the heavy IO is on another disk (in my case), see https://forums.gentoo.org/viewtopic-p-5958024.html |
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devsk
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Joined: 24 Oct 2003
Posts: 3003
Location: Bay Area, CA
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sidamos
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Joined: 16 Dec 2007
Posts: 246
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| Posted: Sat Sep 05, 2009 8:32 pm Post subject: |
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This link does not work. |
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devsk
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Joined: 24 Oct 2003
Posts: 3003
Location: Bay Area, CA
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| Posted: Sun Sep 06, 2009 3:03 am Post subject: |
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| sidamos wrote: |
This link does not work. |
I just clicked on in your post and it did work! anyway, here is the relevant part:
| Quote: |
The kernel developers have been working on improvements to desktop interactivity, particularly when it's under memory pressure since the last release, version 2.6.30, in June.
Desktop applications can experience long and noticeable pauses when the application's code path jumps to a part of the code that is not cached in memory and needs to be read from the disk, which is slower.
However, recent kernel memory management scalability work can result in a desktop environment with poor interactivity as applications become unresponsive too easily.
In version 2.6.31, some heuristics have been used to make it much harder to move the “mapped executable pages” out of the list of active pages, according to Kernelnewbies.org.
“The result is an improved desktop experience; benchmarks on memory tight desktops show clock time and major faults reduced by 50 per cent, and pswpin numbers (memory reads from disk) are reduced to about one-third. That means X desktop responsiveness is doubled under high memory pressure.”
Furthermore, memory flushing benchmarks in a file server shows the number of major faults going from 50 to 3 during 10 per cent cache hot reads. |
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keenblade
Veteran
Joined: 03 Oct 2004
Posts: 1087
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| Posted: Sun Sep 06, 2009 7:42 am Post subject: |
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| devsk wrote: | something brewing in the 2.6.31 release, which may be good news. anyone running 2.6.31 RCs here?
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I have 2.6.31-rc5 here. Here the interbench resulsts:
| Code: |
Using 979314 loops per ms, running every load for 30 seconds
Benchmarking kernel 2.6.31-rc5 at datestamp 200909060950
--- Benchmarking simulated cpu of Audio in the presence of simulated ---
Load Latency +/- SD (ms) Max Latency % Desired CPU % Deadlines Met
None 0.085 +/- 0.379 6.64 100 100
Video 0.122 +/- 0.652 11.8 100 100
X 0.208 +/- 1.29 16.3 100 100
Burn 0.035 +/- 0.211 4.15 100 100
Write 0.255 +/- 1.36 21.5 100 100
Read 0.117 +/- 0.875 13.6 100 100
Compile 0.04 +/- 0.383 8.73 100 100
Memload 0.024 +/- 0.101 2.29 100 100
--- Benchmarking simulated cpu of Video in the presence of simulated ---
Load Latency +/- SD (ms) Max Latency % Desired CPU % Deadlines Met
None 0.101 +/- 1.2 31.9 99.9 99.7
X 0.275 +/- 2.32 35.8 99.4 99.2
Burn 0.072 +/- 1.97 81.8 99.9 99.9
Write 0.242 +/- 2.6 67.3 99.7 99.4
Read 0.093 +/- 0.926 32.4 100 99.9
Compile 0.076 +/- 0.881 27.1 100 99.9
Memload 0.074 +/- 0.486 16.7 100 99.9
--- Benchmarking simulated cpu of X in the presence of simulated ---
Load Latency +/- SD (ms) Max Latency % Desired CPU % Deadlines Met
None 0 +/- 0.00419 0.063 100 100
Video 0 +/- 0.00283 0.037 100 100
Burn 6.15 +/- 36.5 434 52.5 51.1
Write 0 +/- 0.00193 0.023 100 100
Read 0 +/- 0.00198 0.025 100 100
Compile 9.32 +/- 39.4 408 33.5 29.8
Memload 0 +/- 0.00567 0.068 100 100
--- Benchmarking simulated cpu of Gaming in the presence of simulated ---
Load Latency +/- SD (ms) Max Latency % Desired CPU
None 0.016 +/- 0.395 9.57 100
Video 0.428 +/- 5.17 103 99.6
X 0.355 +/- 5.11 103 99.6
Burn 59.1 +/- 140 952 62.9
Write 0.132 +/- 1.33 22.9 99.9
Read 0.097 +/- 1.77 38.2 99.9
Compile 49.3 +/- 89.1 911 67
Memload 0 +/- 0 0 100
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Note : I don't know how to interpret these results, but it seemed slow to me. Kernel is from linus git. No patch used and I have ccache, if it matters.
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Anyway it's all the same at the end...
Need help to get it working: "x-fi surround 5.1" |
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devsk
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Joined: 24 Oct 2003
Posts: 3003
Location: Bay Area, CA
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| Posted: Sun Sep 06, 2009 4:18 pm Post subject: |
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| I think its the relative interpretation which may be useful. If you have 2.6.30 (or any other older) kernel, then boot into it and re-run interbench and let's see what numbers it throws up. |
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Elv13
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Location: Socialist land of North America
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d-fens
Tux's lil' helper
Joined: 09 Jan 2004
Posts: 93
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| Posted: Tue Sep 08, 2009 1:03 pm Post subject: |
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sounds promising, a pity that i can't try it this week - but one question remains for me:
does the optimized (reduced) disk access just work around the root problem, the slow disk access starting from 2.18? |
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BitJam
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Joined: 12 Aug 2003
Posts: 2513
Location: Silver City, NM
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| Posted: Thu Sep 10, 2009 1:30 am Post subject: |
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I've been running amd64 for a couple of years and here is what I've noticed. As long as I had only one hard drive on the system, I never had any problem. Then as soon as I got a 2nd hard drive, transfer of large files from one drive to the other would be dog slow.
I've been recently playing with LiveUSBs and I've noticed something very strange. Transfer of large files to the usb drive is fairly fast if the usb is formated with fat32 but when I format the usb with ext2, the transfers become dog slow, such as 0.5 megabytes per second.
I've seen this on two out of two usb drives I've tested. |
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devsk
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Joined: 24 Oct 2003
Posts: 3003
Location: Bay Area, CA
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| Posted: Thu Sep 10, 2009 4:40 am Post subject: |
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| 2.6.31 goes stable. Will try it later tomorrow. Anybody else up for some benchmarking and comparisons with respect to this bug? |
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mamunata
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Joined: 30 Nov 2004
Posts: 169
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| Posted: Thu Sep 10, 2009 4:02 pm Post subject: |
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| devsk wrote: | | 2.6.31 goes stable. Will try it later tomorrow. Anybody else up for some benchmarking and comparisons with respect to this bug? |
I've compiled 2.6.31 but almost no difference:
-hdparm shows even slower speed - about 20MB/s on my laptop (wit 2.6.30 was 25MB/s)
-on heavy disk load desktop environment responds slowly and system load is 2-3
-swap is used rarely |
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devsk
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Joined: 24 Oct 2003
Posts: 3003
Location: Bay Area, CA
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| Posted: Thu Sep 10, 2009 6:55 pm Post subject: |
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| mamunata wrote: | | devsk wrote: | | 2.6.31 goes stable. Will try it later tomorrow. Anybody else up for some benchmarking and comparisons with respect to this bug? |
I've compiled 2.6.31 but almost no difference:
-hdparm shows even slower speed - about 20MB/s on my laptop (wit 2.6.30 was 25MB/s)
-on heavy disk load desktop environment responds slowly and system load is 2-3
-swap is used rarely |
Thanks for replying because I was gonna do it today. I think I am gonna just pass the 2.6.31 release then. |
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Elv13
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Joined: 13 Nov 2005
Posts: 388
Location: Socialist land of North America
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| Posted: Sat Sep 12, 2009 2:42 am Post subject: |
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So far so good for me! Kernel 2.6.30 was a huge improvement over 2.6.2[0-9] and 2.6.31 seem to ba as stable and fast. And I finally removed debugging support from my kernel, I hope to never have it enable again :p. I think this solve the issue in my case, 64bit Linux is now exploiting the whole potential of my computer!
EDIT: Ignore my comment, skip this kernel, it suck, I am reverting to 2.6.30 right now. |
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devsk
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Joined: 24 Oct 2003
Posts: 3003
Location: Bay Area, CA
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| Posted: Sat Sep 12, 2009 3:10 am Post subject: |
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| Elv13 wrote: | So far so good for me! Kernel 2.6.30 was a huge improvement over 2.6.2[0-9] and 2.6.31 seem to ba as stable and fast. And I finally removed debugging support from my kernel, I hope to never have it enable again :p. I think this solve the issue in my case, 64bit Linux is now exploiting the whole potential of my computer!
EDIT: Ignore my comment, skip this kernel, it suck, I am reverting to 2.6.30 right now. |
what happened? elaborate please. |
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Gentoo on AMD64
