* Al Boldi <[EMAIL PROTECTED]> wrote: > I have narrowed it down a bit to add_wait_runtime.
the scheduler is a red herring here. Could you "strace -ttt -TTT" one of the glxgears instances (and send us the cfs-debug-info.sh output, with CONFIG_SCHED_DEBUG=y and CONFIG_SCHEDSTATS=y as requested before) so that we can have a closer look? i reproduced something similar and there the stall is caused by 1+ second select() delays on the X client<->server socket. The scheduler stats agree with that: se.sleep_max : 2194711437 se.block_max : 0 se.exec_max : 977446 se.wait_max : 1912321 the scheduler itself had a worst-case scheduling delay of 1.9 milliseconds for that glxgears instance (which is perfectly good - in fact - excellent interactivity) - but the task had a maximum sleep time of 2.19 seconds. So the 'glitch' was not caused by the scheduler. Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/