I've been meaning to post this change for a long time, and have been negligent about it.
The pthread_setschedparam() hack that helps pd's audio not drop on OSX is absolutely fatal when used with GEM. The reason for this is that OSX uses OpenGL for the entire UI and GL requires context switches to handle multiple applications sharing the hardware. When Pd sets it's pthread priority higher than the UI, this context switch can be blocked resulting in a complete lockout of UI events as GEM grabs all the CPU resources and refuses to relinquish the context.
The fix is to add the -rt option as prerequisite and not make this the default action (a check to make sure GEM is not loaded would be good to have as well):
#ifdef MACOSX
if (sys_hipriority) { struct sched_param param; int policy = SCHED_RR; int err; param.sched_priority = 80; // adjust 0 : 100 post("pd: real-time mode - using pthread_setschedparam\n"); err = pthread_setschedparam(pthread_self(), policy, ¶m); if (err) post("warning: high priority scheduling failed\n"); } #endif /* MACOSX */
Hi,
I was just about applying this to the CVS version, together with Yves threading patch, but I think it would be better to leave this decision up to you.
Guenter
On Sun, 23 Nov 2003, cgc wrote:
I've been meaning to post this change for a long time, and have been negligent about it.
The pthread_setschedparam() hack that helps pd's audio not drop on OSX is absolutely fatal when used with GEM. The reason for this is that OSX uses OpenGL for the entire UI and GL requires context switches to handle multiple applications sharing the hardware. When Pd sets it's pthread priority higher than the UI, this context switch can be blocked resulting in a complete lockout of UI events as GEM grabs all the CPU resources and refuses to relinquish the context.
The fix is to add the -rt option as prerequisite and not make this the default action (a check to make sure GEM is not loaded would be good to have as well):
#ifdef MACOSX
if (sys_hipriority) {struct sched_param param; int policy = SCHED_RR; int err; param.sched_priority = 80; // adjust 0 : 100 post("pd: real-time mode - using pthread_setschedparam\n"); err = pthread_setschedparam(pthread_self(), policy, ¶m); if (err) post("warning: high priority scheduling failed\n"); } #endif /* MACOSX */
OK.. I've added an "nrt" flag so that on Mac the default ("rt") acts as it did before... When I get started on 0.38 I can make linux choose "rt" automatically if it's setuid.
cheers Miller
On Sun, Nov 23, 2003 at 03:18:21PM -0600, cgc wrote:
I've been meaning to post this change for a long time, and have been negligent about it.
The pthread_setschedparam() hack that helps pd's audio not drop on OSX is absolutely fatal when used with GEM. The reason for this is that OSX uses OpenGL for the entire UI and GL requires context switches to handle multiple applications sharing the hardware. When Pd sets it's pthread priority higher than the UI, this context switch can be blocked resulting in a complete lockout of UI events as GEM grabs all the CPU resources and refuses to relinquish the context.
The fix is to add the -rt option as prerequisite and not make this the default action (a check to make sure GEM is not loaded would be good to have as well):
#ifdef MACOSX
if (sys_hipriority) {struct sched_param param; int policy = SCHED_RR; int err; param.sched_priority = 80; // adjust 0 : 100 post("pd: real-time mode - using pthread_setschedparam\n"); err = pthread_setschedparam(pthread_self(), policy, ¶m); if (err) post("warning: high priority scheduling failed\n"); } #endif /* MACOSX */
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cgc -
guenter geiger -
Miller Puckette