On 04/19/2014 06:18 PM, Ralf Mardorf wrote: > On Sat, 2014-04-19 at 16:42 +0200, Robin Gareus wrote: >> On 04/19/2014 04:13 PM, Jeremy Jongepier wrote: >>> Why not use Jack2's built-in alsarawmidi driver? >> >> because it [excuse my language] sucks. very bad timing & jitter. > > In the past I used jack2's -Xalsarawmidi option to get rid of bad timing > and jitter. I can't speak for current jack1 and jack2, but some time ago > -Xalsarawmidi improved those things a lot compared to jack1, which > didn't provide this option and compared to jack2 without using this > option. Indeed they're pretty close these days. That was not true last time I measured it. a2jmidid still has a slight edge, here. Same latency as alsarawmidi but less jitter. jackd2 from git (ab409a65df). measured with https://github.com/x42/jack_midi_latency using a PreSonus 1818VSL on a thinkpad x60s. linux 3.2.35 SMP PREEMPT RT ====================== ## jackd -S -dalsa -dhw:2 -r48000 -p64 -n2 -Xraw JACK settings: samplerate: 48000, samples/period: 64 probable nominal jack latency: 128 [samples] = 2.67 [ms] TOTAL: 10000 MIDI events sent+received. min= 183 max= 209 range= 26 avg= 193.6 dev= 4.69 [samples] min= 3.81 max= 4.35 range= 0.54 avg= 4.0 dev= 0.10 [ms] 0.00 .. 3.78 [ms]: 0 3.78 .. 3.80 [ms]: 2 # 3.80 .. 3.81 [ms]: 0 3.81 .. 3.83 [ms]: 13 # 3.83 .. 3.85 [ms]: 44 # 3.85 .. 3.86 [ms]: 127 # 3.86 .. 3.88 [ms]: 0 3.88 .. 3.89 [ms]: 142 # 3.89 .. 3.91 [ms]: 270 ## 3.91 .. 3.93 [ms]: 222 ## 3.93 .. 3.94 [ms]: 491 #### 3.94 .. 3.96 [ms]: 0 3.96 .. 3.98 [ms]: 4930 ########################################### 3.98 .. 3.99 [ms]: 263 ## 3.99 .. 4.01 [ms]: 174 # 4.01 .. 4.03 [ms]: 0 4.03 .. 4.04 [ms]: 159 # 4.04 .. 4.06 [ms]: 152 # 4.06 .. 4.07 [ms]: 612 ###### 4.07 .. 4.09 [ms]: 200 ## 4.09 .. 4.11 [ms]: 0 4.11 .. 4.12 [ms]: 298 ### 4.12 .. 4.14 [ms]: 170 # 4.14 .. 4.16 [ms]: 188 # 4.16 .. 4.17 [ms]: 132 # 4.17 .. 4.19 [ms]: 0 4.19 .. 4.20 [ms]: 733 ####### 4.20 .. 4.22 [ms]: 490 #### 4.22 .. 4.24 [ms]: 153 # 4.24 .. inf [ms]: 34 # ====================== ## jackd -S -dalsa -dhw:2 -r48000 -p64 -n2 ## a2jmidid -e JACK settings: samplerate: 48000, samples/period: 64 probable nominal jack latency: 128 [samples] = 2.67 [ms] TOTAL: 10000 MIDI events sent+received. min= 184 max= 209 range= 25 avg= 193.0 dev= 4.09 [samples] min= 3.83 max= 4.35 range= 0.52 avg= 4.0 dev= 0.09 [ms] 0.00 .. 3.80 [ms]: 0 3.80 .. 3.83 [ms]: 48 # 3.83 .. 3.85 [ms]: 73 # 3.85 .. 3.88 [ms]: 99 # 3.88 .. 3.91 [ms]: 131 # 3.91 .. 3.93 [ms]: 164 # 3.93 .. 3.96 [ms]: 6318 ############################################ 3.96 .. 3.98 [ms]: 252 # 3.98 .. 4.01 [ms]: 174 # 4.01 .. 4.04 [ms]: 133 # 4.04 .. 4.06 [ms]: 906 ####### 4.06 .. 4.09 [ms]: 223 # 4.09 .. 4.11 [ms]: 151 # 4.11 .. 4.14 [ms]: 96 # 4.14 .. 4.17 [ms]: 220 # 4.17 .. 4.19 [ms]: 623 #### 4.19 .. inf [ms]: 388 ### ====================== ## jackd -S -dalsa -dhw:2 -r48000 -p64 -n2 -Xseq interestingly has the lowest latency (one period less) but 3 times the jitter. JACK settings: samplerate: 48000, samples/period: 64 probable nominal jack latency: 128 [samples] = 2.67 [ms] TOTAL: 10000 MIDI events sent+received. min= 128 max= 179 range= 51 avg= 154.2 dev= 13.59 [samples] min= 2.67 max= 3.73 range= 1.06 avg= 3.2 dev= 0.28 [ms] 0.00 .. 2.57 [ms]: 53 # 2.57 .. 2.69 [ms]: 542 ############## 2.69 .. 2.81 [ms]: 1834 ############################################ 2.81 .. 2.93 [ms]: 1078 ############################# 2.93 .. 3.05 [ms]: 764 #################### 3.05 .. 3.18 [ms]: 1750 ######################################### 3.18 .. 3.30 [ms]: 887 ######################## 3.30 .. 3.42 [ms]: 1164 ############################### 3.42 .. 3.54 [ms]: 1720 ######################################## 3.54 .. 3.66 [ms]: 207 ##### 3.66 .. 3.78 [ms]: 0 3.78 .. inf [ms]: 0 ciao, robin _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
