[LAD] alsa sequencer latency ( snd_seq_ev_schedule_real ) - need help!

Hiho, I am experiencing strange things with some code that uses the ALSA sequencer, with the function snd_seq_ev_schedule_real(evt, mQueue, 1, &time); The timing of this is unreliable. At times it goes as expected for a while, but then after some time large delays (minutes, instead of the expected latency of 0.1 second) are introduced. Does anyone have any idea what the problem could be? I have a code snippet below. In case anyone wants to try (the app is SuperCollider, you need the latest svn). I'm on a Debian kernel (2.6.24-1-amd64 #1 SMP Thu Mar 27 16:52:38 UTC 2008 x86_64 GNU/Linux), in case that is relevant. sincerely, Marije int SC_AlsaMidiClient::sendEvent(int outputIndex, int uid, snd_seq_event_t* evt, float late) { snd_seq_real_time time; if ((outputIndex < 0) || (outputIndex >= mNumOutPorts)) return errIndexOutOfRange; snd_seq_ev_set_source(evt, mOutPorts[outputIndex]); if (uid == 0) { // send to all subscribed ports snd_seq_ev_set_subs(evt); } else { // send to specific port int cid, pid; SC_AlsaParseUID(uid, cid, pid); snd_seq_ev_set_dest(evt, cid, pid); } long latelong; if (late > 0.f) { latelong = (long) (late * 1000000000); // new time calculation. The old one was not correct time.tv_sec = (long)(latelong / 1000000000); // seconds time.tv_nsec = (long)(latelong % 1000000000); // nanoseconds } else { time.tv_sec = time.tv_nsec = 0; } // evt->flags = evt->flags | SND_SEQ_TIME_STAMP_REAL; post("MIDI (ALSA): sending event, time %i, %i, late %f, latelong %i\n", time.tv_sec, time.tv_nsec, late, latelong); snd_seq_ev_schedule_real(evt, mQueue, 1, &time); snd_seq_event_output_direct(mHandle, evt); // snd_seq_event_output(mHandle, evt); return errNone; }