Re: [Jackit-devel] Re: Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.31-19

Florian Schmidt
2004-12-02T21:19:21Z

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On Thu, 2 Dec 2004 21:03:18 +0100
Florian Schmidt <mista.tapas@gmx.net> wrote:

> On 02 Dec 2004 11:32:49 -0600
> "Jack O'Quin" <joq@io.com> wrote:
>
> > Florian Schmidt <mista.tapas@gmx.net> writes:
> >
> > > Hmm, i must have missed something in jackd's source. i thought
> > > control->process() directly calls the clients process callback..
> >
> > It does.
>
> Then either i have misunderstood how it works, or the mechanism is still
> buggy.. Wrote mail to Ingo. Will report to jackit-devel when i get an
> answer.

PEBCAK :) Here's the corrected patch:

--- libjack/client.c.orig 2004-12-02 17:55:04.000000000 +0100
+++ libjack/client.c 2004-12-02 22:04:06.000000000 +0100
@@ -1238,6 +1238,9 @@
if (control->sync_cb)
jack_call_sync_client (client);

+ // enable atomicity check for RP kernels
+ gettimeofday(1,1);
+
if (control->process) {
if (control->process (control->nframes,
control->process_arg)
@@ -1247,7 +1250,10 @@
} else {
control->state = Finished;
}
-
+
+ // disable atomicity check
+ gettimeofday(1,0);
+
if (control->timebase_cb)
jack_call_timebase_master (client);

seems to work well with my changed jack_test client (this one sleeps in
the 1000th call of the process callback and thuis triggers this trace
and aborts as it doesn't handle SIGUSR2). test client attached.

Dec 2 22:05:10 mango kernel: jack_test:3043 userspace BUG: scheduling in user-atomic context!
Dec 2 22:05:10 mango kernel: [<c02a38b6>] schedule+0x76/0x130 (8)
Dec 2 22:05:10 mango kernel: [<c02a44c5>] schedule_timeout+0x85/0xe0 (36)
Dec 2 22:05:10 mango kernel: [<c01e2f02>] copy_from_user+0x42/0x80 (48)
Dec 2 22:05:10 mango kernel: [<c011ceb0>] process_timeout+0x0/0x10 (8)
Dec 2 22:05:10 mango kernel: [<c011cfae>] sys_nanosleep+0xde/0x170 (20)
Dec 2 22:05:10 mango kernel: [<c01025cb>] syscall_call+0x7/0xb (52)

flo

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#include <jack/jack.h>
#include <iostream>
#include <sstream>
#include <unistd.h>
#include <signal.h>

jack_client_t *client;
jack_port_t *iport;
jack_port_t *oport;

int wasted_loops = 0;

int sleep_seconds = 1;
int sleep_in_period = 1000;
int counter = 0;

int process(jack_nframes_t frames, void *arg) {

// std::cout << "process callback" << std::endl;
jack_default_audio_sample_t *ibuf;
ibuf = (jack_default_audio_sample_t*)jack_port_get_buffer(iport, frames);

jack_default_audio_sample_t *obuf;
obuf = (jack_default_audio_sample_t*)jack_port_get_buffer(oport, frames);

for (jack_nframes_t frame = 0; frame < frames; frame++) {
for (int i = 0; i < wasted_loops; ++i) {
// do nothing
}
obuf[frame] = ibuf[frame];
}
counter++;
if (counter == sleep_in_period) {
sleep(sleep_seconds);
}

return 0;
}
void signalled(int sig) {
std::cout << "signalled" << std::endl;
}

int main(int argc, char *argv[]) {
// default = 60 seconds
unsigned int seconds_to_run = 60;
if (argc > 1) {
std::stringstream sec_stream;
sec_stream << argv[1];
sec_stream >> seconds_to_run;
if (argc > 2) {
std::stringstream waste_stream;
waste_stream << argv[2];
waste_stream >> wasted_loops;
std::cout << "wasted loops: " << wasted_loops << std::endl;
}
}

// signal(SIGUSR2, signalled);

std::cout << "seconds to run: " << seconds_to_run << std::endl;

std::stringstream pid_stream;
pid_stream << getpid();

std::cout << "client_new" << std::endl;
client = jack_client_new(pid_stream.str().c_str());

std::cout << "port_register." << std::endl;
iport = jack_port_register(client, "in", JACK_DEFAULT_AUDIO_TYPE, JackPortIsInput|JackPortIsTerminal, 0);
oport = jack_port_register(client, "out", JACK_DEFAULT_AUDIO_TYPE, JackPortIsTerminal|JackPortIsOutput, 0);

std::cout << "set_process_callback" << std::endl;
jack_set_process_callback(client, process, 0);

std::cout << "activate" << std::endl;
jack_activate(client);

std::cout << "running" << std::endl;

// while(1) {sleep(1);};
sleep(seconds_to_run);

jack_deactivate(client);
jack_client_close(client);
}