From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ahern Subject: Re: [PATCH 1/6] trace: add tracepoints to timekeeping code - xtime changes Date: Fri, 17 Jun 2011 08:13:19 -0600 Message-ID: <4DFB60FF.1080500@gmail.com> References: <1307490806-24548-1-git-send-email-dsahern@gmail.com> <1307490903-24600-1-git-send-email-dsahern@gmail.com> <20110617132322.GB25197@somewhere.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pz0-f46.google.com ([209.85.210.46]:41206 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756962Ab1FQONV (ORCPT ); Fri, 17 Jun 2011 10:13:21 -0400 In-Reply-To: <20110617132322.GB25197@somewhere.redhat.com> Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: Frederic Weisbecker Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, acme@ghostprotocols.net, mingo@elte.hu, peterz@infradead.org, paulus@samba.org, tglx@linutronix.de, johnstul@us.ibm.com, rostedt@goodmis.org On 06/17/2011 07:23 AM, Frederic Weisbecker wrote: > On Tue, Jun 07, 2011 at 05:55:03PM -0600, David Ahern wrote: >> Trace points in timekeeping.c where xtime is modified by a user >> or ntp. >> >> Signed-off-by: David Ahern >> --- >> include/trace/events/timekeeping.h | 43 ++++++++++++++++++++++++++++++++++++ >> kernel/time/timekeeping.c | 8 ++++++ >> 2 files changed, 51 insertions(+), 0 deletions(-) >> create mode 100644 include/trace/events/timekeeping.h >> >> diff --git a/include/trace/events/timekeeping.h b/include/trace/events/timekeeping.h >> new file mode 100644 >> index 0000000..3d5d083 >> --- /dev/null >> +++ b/include/trace/events/timekeeping.h >> @@ -0,0 +1,43 @@ >> +#undef TRACE_SYSTEM >> +#define TRACE_SYSTEM timekeeping >> + >> +#if !defined(_TRACE_TIMEKEEP_H) || defined(TRACE_HEADER_MULTI_READ) >> +#define _TRACE_TIMEKEEP_H >> + >> +#include >> +#include >> + >> +DECLARE_EVENT_CLASS(tod_template, >> + >> + TP_PROTO(const struct timespec *tv), >> + >> + TP_ARGS(tv), >> + >> + TP_STRUCT__entry( >> + __field( __kernel_time_t, tv_sec) >> + __field( long, tv_nsec) >> + ), >> + >> + TP_fast_assign( >> + __entry->tv_sec = tv->tv_sec; >> + __entry->tv_nsec = tv->tv_nsec; >> + ), >> + >> + TP_printk("tv_sec=%ld tv_nsec=%ld", __entry->tv_sec, __entry->tv_nsec) >> +); >> + >> +DEFINE_EVENT(tod_template, settimeofday, >> + TP_PROTO(const struct timespec *tv), >> + TP_ARGS(tv)); >> + >> +DEFINE_EVENT(tod_template, timekeeping_inject_offset, >> + TP_PROTO(const struct timespec *tv), >> + TP_ARGS(tv)); >> + >> +DEFINE_EVENT(tod_template, timekeeping_inject_sleeptime, >> + TP_PROTO(const struct timespec *tv), >> + TP_ARGS(tv)); > > Does the fact it's any of the three way of updating xtime make any > difference from the user point of view? This use case only cares that xtime is updated. > > If not can we rather factorize that in a single settimeofday tracepoint? > Or update_time_of_day if we don't want to confuse the user with the > syscall. Peter and Thomas expressed interest in timekeeping tracepoints. How the update happens might be wanted. If desired I can consolidate xtime = *tv into a single update function and put the trace point there. David