Re: [PATCH v1] timer:clock:ptp: add support the dynamic posix clock alarm set for ptp
From: Richard Cochran <richardcochran@gmail.com>
Date: 2019-05-07 13:49:58
Also in:
linuxppc-dev, lkml, netdev
On Sun, May 05, 2019 at 05:02:05AM +0000, Po Liu wrote:
Current kernel code do not support the dynamic posix clock alarm set.
This code would support it by the posix timer structure.
319 const struct k_clock clock_posix_dynamic = {
320 .clock_getres = pc_clock_getres,
321 .clock_set = pc_clock_settime,
322 .clock_get = pc_clock_gettime,
323 .clock_adj = pc_clock_adjtime,
324 + .timer_create = pc_timer_create,
325 + .timer_del = pc_timer_delete,
326 + .timer_set = pc_timer_set,
327 + .timer_arm = pc_timer_arm,
}Sorry, NAK, since we decided some time ago not to support timer_* operations on dynamic clocks. You get much better application level timer performance by synchronizing CLOCK_REALTIME to your PHC and using clock_nanosleep() with CLOCK_REALTIME or CLOCK_MONOTONIC.
This won't change the user space system call code. Normally the user space set alarm by timer_create() and timer_settime(). Reference code are tools/testing/selftests/ptp/testptp.c.
That program still has misleading examples. Sorry about that. I'll submit a patch to remove them.
+static int pc_timer_create(struct k_itimer *new_timer)
+{
+ return 0;
+}
+This of course would never work. Consider what happens when two or more timers are created and armed. Thanks, Richard _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel