Re: [linux-audio-dev] Realtime problems with midi/osc sequencer
You could also try sigaction and setitimer.
I've had good timing results with this approach in the past.
(I haven't tried it for audio tasks though.)
Steve
On 3/11/07, Robin Gareus <[EMAIL PROTECTED]> wrote:
Christian wrote:
> Robin Gareus schrieb:
>>> usleep( iTick-( passedTime-startTime ) );
>> AFAIR usleep is not exact! - did you
>> echo 1024 > /proc/sys/dev/rtc/max-user-freq ?
>
>> try sth like:
>
>> void select_sleep (int usec) {
>> fd_set fd;
>> int max_fd=0;
>> struct timeval tv = { 0, 0 };
>> tv.tv_sec = 0; tv.tv_usec = usec;
>
>> FD_ZERO(&fd);
>> if (remote_en) {
>> max_fd=remote_fd_set(&fd);
>> }
>
>> select(max_fd, &fd, NULL, NULL, &tv);
>
>> }
>
>
>
> Interesting timing approach.
> But I can't find remote_en and remote_fd_set in the man pages.
> What does these arguments stand for?
sorry, cut the 3 "if(remote_en)" lines - I was too quick with pasting &
sending the mail - remote_en is some global var. that allows to
interrupt the sleep, if some other-event occurs... - actually you'd only
needed "select (0,&fd,0,0,&tv);"
anyway clock_nanosleep seems better; at least it takes less code
to set it up. I did not know about it, and it's even POSIX, how cool!
#robin
Re: [linux-audio-dev] Realtime problems with midi/osc sequencer
Christian wrote:
> Robin Gareus schrieb:
>>> usleep( iTick-( passedTime-startTime ) );
>> AFAIR usleep is not exact! - did you
>> echo 1024 > /proc/sys/dev/rtc/max-user-freq ?
>
>> try sth like:
>
>> void select_sleep (int usec) {
>> fd_set fd;
>> int max_fd=0;
>> struct timeval tv = { 0, 0 };
>> tv.tv_sec = 0; tv.tv_usec = usec;
>
>> FD_ZERO(&fd);
>> if (remote_en) {
>> max_fd=remote_fd_set(&fd);
>> }
>
>> select(max_fd, &fd, NULL, NULL, &tv);
>
>> }
>
>
>
> Interesting timing approach.
> But I can't find remote_en and remote_fd_set in the man pages.
> What does these arguments stand for?
sorry, cut the 3 "if(remote_en)" lines - I was too quick with pasting &
sending the mail - remote_en is some global var. that allows to
interrupt the sleep, if some other-event occurs... - actually you'd only
needed "select (0,&fd,0,0,&tv);"
anyway clock_nanosleep seems better; at least it takes less code
to set it up. I did not know about it, and it's even POSIX, how cool!
#robin
Re: [linux-audio-dev] Realtime problems with midi/osc sequencer
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> I'd suggest using clock_nanosleep() and clock_gettime() with
> clockid=CLOCK_MONOTONIC.
> This is the "more right" approach than select/gettimeofday().
>
>
> Dmitry.
Yeah clock_nanosleep did it!
I got a stable absolute bpm exact midi clock.
I'll test the osc messages tomorrow( I've to rewrite some stuff of my
first sequencer ).
Whooo, thanks alot.
Christian
p.s.:
The Code:
[CODE]
void Timer::runThread()
{
std::list::iterator iter;
timespec timeOut;
int shortTickCount=0;
int longTickCount=0;
int midiTickCount=0;
struct sched_param rtparam;
memset (&rtparam, 0, sizeof (rtparam));
rtparam.sched_priority = 99;
pthread_setschedparam (thread, SCHED_FIFO, &rtparam);
while( !bRunning )
usleep ( 100 );
clock_gettime( CLOCK_MONOTONIC, &timeOut );
for( iter=seqs.begin(); iter!=seqs.end(); iter++ )
{
lo_send_timestamped( iter->address, LO_TT_IMMEDIATE,
"/timer/tick",
"iii", iTact, iShortTick, iLongTick );
}
while( !bQuit )
{
if( shortTickCount == 3 )
{
iShortTick++;
shortTickCount=0;
if( iShortTick == 256 )
{
iShortTick=0;
iLongTick=0;
iTact++;
}
for( iter=seqs.begin(); iter!=seqs.end(); iter++ )
{
lo_send_timestamped( iter->address,
LO_TT_IMMEDIATE, "/timer/tick",
"iii", iTact, iShortTick, iLongTick );
}
}
if( longTickCount == 4 )
{
longTickCount=0;
iLongTick++;
}
if( midiTickCount == 8 )
{
midiTickCount=0;
midiOut->sendMessage( &midiMsg );
}
shortTickCount++;
longTickCount++;
midiTickCount++;
timeOut.tv_nsec+=iTick*1000;
if( timeOut.tv_nsec >10 )
{
timeOut.tv_sec++;
timeOut.tv_nsec=timeOut.tv_nsec-10;
}
clock_nanosleep( CLOCK_MONOTONIC, TIMER_ABSTIME, &timeOut, NULL
);
}
pthread_exit( 0 );
}
[/CODE]
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Re: [linux-audio-dev] Realtime problems with midi/osc sequencer
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Dmitry Baikov schrieb: > 4ms means you have 250Hz kernel tick. Set it to 1024Hz or better try > tickless setup. /proc/asound/timers says: G0: system timer : 1000.000us (1000 ticks) G1: RTC timer : 976.562us (1 ticks) Seq24 for example is running correctly so I don't think it's an error in my system setup. -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFF8xSSVC26eJ+o0+0RArk9AKCSPnuk+k0C2iDVF66M3ZIr6b2n1gCfRe5u 1BgsXmwU9hBRjtYq8bmRo5Y= =eIOK -END PGP SIGNATURE-
Re: [linux-audio-dev] Realtime problems with midi/osc sequencer
On 3/10/07, Christian <[EMAIL PROTECTED]> wrote: On the one hand this indicates the thread running stable in realtime but having a restriction to ~4ms/4000µs. Perhaps this is an in-system value 4ms means you have 250Hz kernel tick. Set it to 1024Hz or better try tickless setup. of sleep and the select approach Robin Gareus posted will help out. I'd suggest using clock_nanosleep() and clock_gettime() with clockid=CLOCK_MONOTONIC. This is the "more right" approach than select/gettimeofday(). Dmitry.
Re: [linux-audio-dev] Realtime problems with midi/osc sequencer
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Dmitry Baikov schrieb: > In addition to select() there's also clock_nanosleep(CLOCK_MONOTONIC, > 0, &tv, NULL), which in theory should give best resolution possible. > > To set realtime privileges, use (taken from jack): > > struct sched_param rtparam; > memset (&rtparam, 0, sizeof (rtparam)); > rtparam.sched_priority = priority; > pthread_setschedparam (thread, SCHED_FIFO, &rtparam); > > > > Interesting project, btw. I planned to start something like this myself. > > Please, publish results of your timing experiments - very interesting! > > > Dmitry. > > Taken your code to set the thread to realtime I now get very exactly 78 bpm which don't change much. On the one hand this indicates the thread running stable in realtime but having a restriction to ~4ms/4000µs. Perhaps this is an in-system value of sleep and the select approach Robin Gareus posted will help out. Christian -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFF8w7GVC26eJ+o0+0RAnEfAKCXD2rWLK+MO4kFWyzd7PwtVL/qWgCgnYUi /M3jB2t4fatk/SXnWUKTAe4= =MzSS -END PGP SIGNATURE-
Re: [linux-audio-dev] Realtime problems with midi/osc sequencer
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Robin Gareus schrieb:
>> usleep( iTick-( passedTime-startTime ) );
>
> AFAIR usleep is not exact! - did you
> echo 1024 > /proc/sys/dev/rtc/max-user-freq ?
>
> try sth like:
>
> void select_sleep (int usec) {
> fd_set fd;
> int max_fd=0;
> struct timeval tv = { 0, 0 };
> tv.tv_sec = 0; tv.tv_usec = usec;
>
> FD_ZERO(&fd);
> if (remote_en) {
> max_fd=remote_fd_set(&fd);
> }
>
> select(max_fd, &fd, NULL, NULL, &tv);
>
> }
>
>
>
Interesting timing approach.
But I can't find remote_en and remote_fd_set in the man pages.
What does these arguments stand for?
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Re: [linux-audio-dev] Realtime problems with midi/osc sequencer
In addition to select() there's also clock_nanosleep(CLOCK_MONOTONIC, 0, &tv, NULL), which in theory should give best resolution possible. To set realtime privileges, use (taken from jack): struct sched_param rtparam; memset (&rtparam, 0, sizeof (rtparam)); rtparam.sched_priority = priority; pthread_setschedparam (thread, SCHED_FIFO, &rtparam); Interesting project, btw. I planned to start something like this myself. Please, publish results of your timing experiments - very interesting! Dmitry.
Re: [linux-audio-dev] Realtime problems with midi/osc sequencer
> usleep( iTick-( passedTime-startTime ) );
AFAIR usleep is not exact! - did you
echo 1024 > /proc/sys/dev/rtc/max-user-freq ?
try sth like:
void select_sleep (int usec) {
fd_set fd;
int max_fd=0;
struct timeval tv = { 0, 0 };
tv.tv_sec = 0; tv.tv_usec = usec;
FD_ZERO(&fd);
if (remote_en) {
max_fd=remote_fd_set(&fd);
}
select(max_fd, &fd, NULL, NULL, &tv);
}
