From: Richard Cochran <richardcochran@gmail.com>
To: Po Liu <po.liu@nxp.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"Y.b. Lu" <yangbo.lu@nxp.com>,
Claudiu Manoil <claudiu.manoil@nxp.com>,
"davem@davemloft.net" <davem@davemloft.net>,
Leo Li <leoyang.li@nxp.com>, Roy Zang <roy.zang@nxp.com>,
Mingkai Hu <mingkai.hu@nxp.com>,
"deepa.kernel@gmail.com" <deepa.kernel@gmail.com>
Subject: Re: [PATCH v1] timer:clock:ptp: add support the dynamic posix clock alarm set for ptp
Date: Tue, 7 May 2019 06:49:52 -0700 [thread overview]
Message-ID: <20190507134952.uqqxmhinv75actbh@localhost> (raw)
In-Reply-To: <1557032106-28041-1-git-send-email-Po.Liu@nxp.com>
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
next prev parent reply other threads:[~2019-05-07 13:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-05 5:02 [PATCH v1] timer:clock:ptp: add support the dynamic posix clock alarm set for ptp Po Liu
2019-05-07 13:49 ` Richard Cochran [this message]
2019-05-08 3:30 ` [EXT] " Po Liu
2019-05-08 14:36 ` Richard Cochran
2019-05-08 17:06 ` Richard Cochran
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