From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751578AbcBMDec (ORCPT ); Fri, 12 Feb 2016 22:34:32 -0500 Received: from mga09.intel.com ([134.134.136.24]:54000 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750857AbcBMDbz (ORCPT ); Fri, 12 Feb 2016 22:31:55 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.22,438,1449561600"; d="scan'208";a="901946507" From: "Christopher S. Hall" To: tglx@linutronix.de, richardcochran@gmail.com, mingo@redhat.com, john.stultz@linaro.org, hpa@zytor.com, jeffrey.t.kirsher@intel.com Cc: "Christopher S. Hall" , x86@kernel.org, linux-kernel@vger.kernel.org, intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, kevin.b.stanton@intel.com, kevin.j.clarke@intel.com Subject: [PATCH v7 2/8] time: Add timekeeping snapshot code capturing system time and counter Date: Fri, 12 Feb 2016 12:25:23 -0800 Message-Id: <1455308729-6280-3-git-send-email-christopher.s.hall@intel.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1455308729-6280-1-git-send-email-christopher.s.hall@intel.com> References: <1455308729-6280-1-git-send-email-christopher.s.hall@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the current timekeeping code there isn't any interface to atomically capture the current relationship between the system counter and system time. ktime_get_snapshot() returns this triple (counter, monotonic raw, realtime) in the system_time_snapshot struct. Signed-off-by: Christopher S. Hall [jstultz: Moved structure definitions around to clean things up] Signed-off-by: John Stultz --- include/linux/timekeeping.h | 18 ++++++++++++++++++ kernel/time/timekeeping.c | 30 ++++++++++++++++++++++++++++++ 2 files changed, 48 insertions(+) diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h index ec89d84..af220e1 100644 --- a/include/linux/timekeeping.h +++ b/include/linux/timekeeping.h @@ -267,6 +267,24 @@ extern void ktime_get_raw_and_real_ts64(struct timespec64 *ts_raw, struct timespec64 *ts_real); /* + * struct system_time_snapshot - simultaneous raw/real time capture with + * counter value + * @cycles: Clocksource counter value to produce the system times + * @real: Realtime system time + * @raw: Monotonic raw system time + */ +struct system_time_snapshot { + cycles_t cycles; + ktime_t real; + ktime_t raw; +}; + +/* + * Simultaneously snapshot realtime and monotonic raw clocks + */ +extern void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot); + +/* * Persistent clock related interfaces */ extern int persistent_clock_is_local; diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 4243d28..89b4695 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -874,6 +874,36 @@ time64_t __ktime_get_real_seconds(void) return tk->xtime_sec; } +/** + * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter + * @systime_snapshot: pointer to struct receiving the system time snapshot + */ +void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot) +{ + struct timekeeper *tk = &tk_core.timekeeper; + unsigned long seq; + ktime_t base_raw; + ktime_t base_real; + s64 nsec_raw; + s64 nsec_real; + cycle_t now; + + do { + seq = read_seqcount_begin(&tk_core.seq); + + now = tk->tkr_mono.read(tk->tkr_mono.clock); + base_real = ktime_add(tk->tkr_mono.base, + tk_core.timekeeper.offs_real); + base_raw = tk->tkr_raw.base; + nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now); + nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, now); + } while (read_seqcount_retry(&tk_core.seq, seq)); + + systime_snapshot->cycles = now; + systime_snapshot->real = ktime_add_ns(base_real, nsec_real); + systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw); +} +EXPORT_SYMBOL_GPL(ktime_get_snapshot); #ifdef CONFIG_NTP_PPS -- 2.1.4