[LAU] alsa-midi-latency-test (v0.0.2) test results survey

Hi All + Jakob, I am moving this conversation onto this list as other people may be interested in this topic. I have just run Jakob alsa-midi-latency-test on my pc Ubuntu 8.10 (intrepid) with the standard kernel 2.6.27-14-generic and get these results pasted below. I feel that this program is important because it measures the real-time performance of the OS and the midi hardware and hopefully it will encourage main stream distributions to improve the out of the box real-time performance. Unfortunately this program says that this test failed on my setup (I am using the Edirol UM-2EX USB MIDI interface but Jakob benchmark results for the UM-2EX has a worst latency of 2.15 ms which is great) The results are MUCH better than on my old Xandros eeepc 701(also results below) which I am using until my faulty eeepc 901A returns from repair. I have a particular interested in this as I am the author of PianoBooster which is aimed at novices as well as advanced pianists and I hope that real-time performance will be improved on future on mainstream standard Linux distributions without requiring lots of tweaks. Maybe we could use this program to test beta distributions to ensure that out of the box real-time performance was up to scratch. I am also planning to use this program to improve the performance of PianoBooster which I know suffers from a number of timing issues. In the meantime what results do you get on your hardware and on your setup? ./alsa-midi-latency-test -o 24:0 -i 24:0 -R -w 1 -r sched_setscheduler: Operation not permitted sample; latency_ms; latency_ms_worst 0; 3.69; 3.69 1; 3.80; 3.80 5; 4.82; 4.82 107; 6.17; 6.17 238; 6.30; 6.30 496; 6.52; 6.52 4712; 6.79; 6.79 8429; 6.82; 6.82 9999; 3.74; 6.82 ... 3.0 - 3.1 ms: 12 # 3.1 - 3.2 ms: 921 ############################################# 3.2 - 3.3 ms: 961 ############################################### 3.3 - 3.4 ms: 969 ############################################### 3.4 - 3.5 ms: 994 ################################################# 3.5 - 3.6 ms: 948 ############################################## 3.6 - 3.7 ms: 944 ############################################## 3.7 - 3.8 ms: 944 ############################################## 3.8 - 3.9 ms: 1022 ################################################## 3.9 - 4.0 ms: 981 ################################################ 4.0 - 4.1 ms: 966 ############################################### 4.1 - 4.2 ms: 137 ####### 4.2 - 4.3 ms: 22 # 4.3 - 4.4 ms: 18 # 4.4 - 4.5 ms: 22 # 4.5 - 4.6 ms: 14 # 4.6 - 4.7 ms: 10 # 4.7 - 4.8 ms: 11 # 4.8 - 4.9 ms: 16 # 4.9 - 5.0 ms: 7 # 5.0 - 5.1 ms: 9 # 5.1 - 5.2 ms: 14 # 5.2 - 5.3 ms: 9 # 5.3 - 5.4 ms: 3 # 5.4 - 5.5 ms: 7 # 5.5 - 5.6 ms: 5 # 5.6 - 5.7 ms: 4 # 5.7 - 5.8 ms: 4 # 5.8 - 5.9 ms: 6 # 5.9 - 6.0 ms: 3 # ... 6.1 - 6.2 ms: 2 # 6.2 - 6.3 ms: 7 # 6.3 - 6.4 ms: 2 # ... 6.5 - 6.6 ms: 1 # ... 6.7 - 6.8 ms: 3 # 6.8 - 6.9 ms: 2 # best latency was 3.04 ms worst latency was 6.82 ms, which is too much. Please check: - if your hardware uses shared IRQs - `watch -n 1 cat /proc/interrupts` while running this test to see, which IRQs the OS is using for your midi hardware, - if you're running this test on a realtime OS - `uname -a` should contain '-rt', - your OS' scheduling priorities - `chrt -p [pidof process name|IRQ-?]`. Have a look at http://www.linuxaudio.org/mailarchive/lat/ to find out, howto fix issues with high midi latencies. ---------- Forwarded message ---------- From: Jakob Flierl <jakob.flierl(a)gmail.com> Date: Thu, Oct 15, 2009 at 11:53 PM Subject: Re: [LAA] Second version of alsa-midi-latency-test released (v0.0.2) To: "Louis B." <louisjbarman(a)googlemail.com> Hi Louis, thanks for testing! The latency values are too big. Which kernel `uname -a` are you running? Can you re-run alsa-midi-latency-test with the options "-R -w 1 -r" and re-send me the results? This will turn on realtime scheduling for the application and make a more "realistic" benchmark. Kind regards, Jakob On Fri, Oct 16, 2009 at 12:44 AM, Louis B. <louisjbarman(a)googlemail.com> wrote: > Wow Thanks that is really useful see my results below. I always new > the EEEPC 701 was bad but now I can measure how bad it really is. My > replacement EEEPC 901A has gone back for repair. > > I now want to sent it through PianoBooster   It should work using the > midi through to link the two programs together and the midi cable to > comlete the loop (pb in Midi through:0 out UM:2 cable UM:2 out to UM:1 > in ./alsa-midi-latency-test -o 14:0 -i 20:0) > > src> ./alsa-midi-latency-test -l >  Port    Client name                      Port name >  14:0    Midi Through                     Midi Through Port-0 >  20:0    UM-2                             UM-2 MIDI 1 >  20:1    UM-2                             UM-2 MIDI 2 > > > I have tried but PB  translates the MIDI input messages (ie the > pianist piano input onto midi channel one. > > I need to try this on good hardware. > > > Thanks > > Louis > > >> alsa-midi-latency-test 0.0.3 >> clock resolution: 0.010000000 s > WARNING: You do not have a high-resolution clock! > >> sampling 10000 midi latency values - please wait ... >> press Ctrl+C to abort test > > sample; latency_ms; latency_ms_worst >     0;       3.16;       3.16 >     8;       7.38;       7.38 >   182;      30.50;      30.50 >  2666;      99.98;      99.98 >  9999;       1.95;      99.98 >> >> ... >  1.2 -  1.3 ms:       58 # >  1.3 -  1.4 ms:      127 # >  1.4 -  1.5 ms:      134 # >  1.5 -  1.6 ms:      128 # >  1.6 -  1.7 ms:      120 # >  1.7 -  1.8 ms:      143 # >  1.8 -  1.9 ms:      135 # >  1.9 -  2.0 ms:      623 #### >  2.0 -  2.1 ms:     7086 ################################################## >  2.1 -  2.2 ms:      135 # >  2.2 -  2.3 ms:      133 # >  2.3 -  2.4 ms:       99 # >  2.4 -  2.5 ms:       92 # >  2.5 -  2.6 ms:       74 # >  2.6 -  2.7 ms:       94 # >  2.7 -  2.8 ms:       64 # >  2.8 -  2.9 ms:       52 # >  2.9 -  3.0 ms:       56 # >  3.0 -  3.1 ms:      242 ## >  3.1 -  3.2 ms:       20 # >  3.2 -  3.3 ms:       28 # >  3.3 -  3.4 ms:       32 # >  3.4 -  3.5 ms:       33 # >  3.5 -  3.6 ms:       37 # >  3.6 -  3.7 ms:       37 # >  3.7 -  3.8 ms:       34 # >  3.8 -  3.9 ms:       27 # >  3.9 -  4.0 ms:       26 # >  4.0 -  4.1 ms:       20 # >  4.1 -  4.2 ms:       16 # >  4.2 -  4.3 ms:       11 # >  4.3 -  4.4 ms:        8 # >  4.4 -  4.5 ms:        4 # >  4.5 -  4.6 ms:       12 # >  4.6 -  4.7 ms:        9 # >  4.7 -  4.8 ms:        3 # >  4.8 -  4.9 ms:        3 # >  4.9 -  5.0 ms:        2 # >  5.0 -  5.1 ms:        2 # >  5.1 -  5.2 ms:        3 # >  5.2 -  5.3 ms:        1 # >  5.3 -  5.4 ms:        2 # >  5.4 -  5.5 ms:        1 # >  5.5 -  5.6 ms:        1 # >  5.6 -  5.7 ms:        1 # > ... >  5.8 -  5.9 ms:        1 # > ... >  7.4 -  7.5 ms:        1 # > ... >  11.5 - 11.6 ms:        1 # > ... >  12.7 - 12.8 ms:        1 # > ... >  13.0 - 13.1 ms:        1 # > ... >  13.6 - 13.7 ms:        1 # > ... >  14.3 - 14.4 ms:        1 # > ... >  14.7 - 14.8 ms:        1 # > ... >  26.3 - 26.4 ms:        1 # > ... >  26.5 - 26.6 ms:        2 # >  26.6 - 26.7 ms:        1 # > ... >  27.4 - 27.5 ms:        1 # > ... >  27.8 - 27.9 ms:        2 # > ... >  28.2 - 28.3 ms:        2 # >  28.3 - 28.4 ms:        1 # > ... >  28.5 - 28.6 ms:        1 # > ... >  28.9 - 29.0 ms:        2 # > ... >  29.2 - 29.3 ms:        1 # > ... >  29.5 - 29.6 ms:        1 # > ... >  29.8 - 29.9 ms:        3 # > ... >  30.1 - 30.2 ms:        1 # >  30.2 - 30.3 ms:        1 # > ... >  30.5 - 30.6 ms:        1 # > ... >  59.7 - 59.8 ms:        1 # > ... >  60.0 - 60.1 ms:        1 # > ... >  99.9 -100.0 ms:        1 # > >> >  best latency was 1.16 ms >  worst latency was 99.98 ms, which is too much. Please check: > >  - if your hardware uses shared IRQs - `watch -n 1 cat /proc/interrupts` >    while running this test to see, which IRQs the OS is using for > your midi hardware, > >  - if you're running this test on a realtime OS - `uname -a` should > contain '-rt', > >  - your OS' scheduling priorities - `chrt -p [pidof process name|IRQ-?]`. > >  Have a look at >  http://www.linuxaudio.org/mailarchive/lat/ >  to find out, howto fix issues with high midi latencies. > > src> >