From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ahern Subject: Re: Information regarding the perf tool Date: Thu, 31 Oct 2013 12:22:29 -0600 Message-ID: <52729FE5.3090109@gmail.com> References: <5266A57F.2000201@bsc.es> <87y55krw6f.fsf@tassilo.jf.intel.com> <52727B0C.5040402@bsc.es> <527287A7.3050908@gmail.com> <5272922E.20007@bsc.es> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------010109070601050601070105" Return-path: Received: from mail-pd0-f170.google.com ([209.85.192.170]:36414 "EHLO mail-pd0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752728Ab3JaSWd (ORCPT ); Thu, 31 Oct 2013 14:22:33 -0400 Received: by mail-pd0-f170.google.com with SMTP id v10so2832014pde.1 for ; Thu, 31 Oct 2013 11:22:33 -0700 (PDT) In-Reply-To: <5272922E.20007@bsc.es> Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: Harald Servat , Andi Kleen Cc: linux-perf-users@vger.kernel.org This is a multi-part message in MIME format. --------------010109070601050601070105 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit On 10/31/13, 11:23 AM, Harald Servat wrote: > Which is the relation between perf_clock() (or local_clock()) and > clock_gettime (CLOCK_MONOTONIC, ). Are they the same? If not, is there a > way to correlate them? Or alternatively, is it possible to call > local_clock() from the userland? We still do not have a means of correlating perf_clock to time-of-day, monotonic or any other clock source. Still trying. Pawell Moll has a couple of patches posted -- one uses an ioctl to get perf_clock timestamps the other makes perf_clock accessible through clock_gettime. See attached. David --------------010109070601050601070105 Content-Type: text/plain; charset=UTF-8; x-mac-type="0"; x-mac-creator="0"; name="0001-perf-POSIX-CLOCK_PERF-to-report-current-time-value.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename*0="0001-perf-POSIX-CLOCK_PERF-to-report-current-time-value.patc"; filename*1="h" >From 5e2d4c81b9e4a82090ec44a24e84223e00a4c5fd Mon Sep 17 00:00:00 2001 From: David Ahern Date: Wed, 23 Oct 2013 16:53:05 +0100 Subject: [PATCH] perf: POSIX CLOCK_PERF to report current time value To co-relate user space events with the perf events stream a current (as in: "what time(stamp) is it now?") time value must be made available. This patch adds a POSIX clock returning the perf_clock() value and accesible from userspace: #include struct timespec ts; clock_gettime(CLOCK_PERF, &ts); Signed-off-by: Pawel Moll Signed-off-by: David Ahern --- include/uapi/linux/time.h | 1 + kernel/events/core.c | 20 ++++++++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/include/uapi/linux/time.h b/include/uapi/linux/time.h index e75e1b6ff27f..9066bf02c867 100644 --- a/include/uapi/linux/time.h +++ b/include/uapi/linux/time.h @@ -56,6 +56,7 @@ struct itimerval { #define CLOCK_BOOTTIME_ALARM 9 #define CLOCK_SGI_CYCLE 10 /* Hardware specific */ #define CLOCK_TAI 11 +#define CLOCK_PERF 12 #define MAX_CLOCKS 16 #define CLOCKS_MASK (CLOCK_REALTIME | CLOCK_MONOTONIC) diff --git a/kernel/events/core.c b/kernel/events/core.c index b073975af05a..98c26fb1d9fd 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -39,6 +39,7 @@ #include #include #include +#include #include "internal.h" @@ -303,6 +304,19 @@ static inline u64 perf_clock(void) } #endif +static int perf_posix_clock_getres(const clockid_t which_clock, + struct timespec *tp) +{ + *tp = ns_to_timespec(TICK_NSEC); + return 0; +} + +static int perf_posix_clock_get(clockid_t which_clock, struct timespec *tp) +{ + *tp = ns_to_timespec(perf_clock()); + return 0; +} + static inline struct perf_cpu_context * __get_cpu_context(struct perf_event_context *ctx) { @@ -7878,6 +7892,10 @@ perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) void __init perf_event_init(void) { + struct k_clock perf_posix_clock = { + .clock_getres = perf_posix_clock_getres, + .clock_get = perf_posix_clock_get, + }; int ret; idr_init(&pmu_idr); @@ -7894,6 +7912,8 @@ void __init perf_event_init(void) ret = init_hw_breakpoint(); WARN(ret, "hw_breakpoint initialization failed with: %d", ret); + posix_timers_register_clock(CLOCK_PERF, &perf_posix_clock); + /* do not patch jump label more than once per second */ jump_label_rate_limit(&perf_sched_events, HZ); -- 1.8.3.4 (Apple Git-47) --------------010109070601050601070105 Content-Type: text/plain; charset=UTF-8; x-mac-type="0"; x-mac-creator="0"; name="perf-Add-ioctl-to-return-perf_clock.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="perf-Add-ioctl-to-return-perf_clock.patch" >From 3601ad205e74a0af22de4421f12a5f0ee0559057 Mon Sep 17 00:00:00 2001 From: Pawel Moll Date: Fri, 1 Feb 2013 14:03:56 +0000 Subject: [PATCH 16/45] perf: Add ioctl to return current time value To co-relate user space events with the perf events stream a current (as in: "what time(stamp) is it now?") time value must be made available. This patch adds a perf ioctl that makes this possible. Signed-off-by: Pawel Moll --- include/uapi/linux/perf_event.h | 1 + kernel/events/core.c | 8 ++++++++ 2 files changed, 9 insertions(+) diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 0b1df41..41cb39e 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -321,6 +321,7 @@ struct perf_event_attr { #define PERF_EVENT_IOC_PERIOD _IOW('$', 4, __u64) #define PERF_EVENT_IOC_SET_OUTPUT _IO ('$', 5) #define PERF_EVENT_IOC_SET_FILTER _IOW('$', 6, char *) +#define PERF_EVENT_IOC_GET_TIME _IOR('$', 7, __u64) enum perf_event_ioc_flags { PERF_IOC_FLAG_GROUP = 1U << 0, diff --git a/kernel/events/core.c b/kernel/events/core.c index 1833bc5..62a44d9 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3543,6 +3543,14 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) case PERF_EVENT_IOC_SET_FILTER: return perf_event_set_filter(event, (void __user *)arg); + case PERF_EVENT_IOC_GET_TIME: + { + u64 time = perf_clock(); + if (copy_to_user((void __user *)arg, &time, sizeof(time))) + return -EFAULT; + return 0; + } + default: return -ENOTTY; } -- 1.7.10.1 --------------010109070601050601070105--