From patchwork Tue Aug 30 10:28:43 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Binoy Jayan X-Patchwork-Id: 74966 Delivered-To: patch@linaro.org Received: by 10.140.29.52 with SMTP id a49csp2072413qga; Tue, 30 Aug 2016 03:29:22 -0700 (PDT) X-Received: by 10.66.62.164 with SMTP id z4mr4775440par.156.1472552962077; Tue, 30 Aug 2016 03:29:22 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id o78si44582051pfi.291.2016.08.30.03.29.21; Tue, 30 Aug 2016 03:29:22 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758030AbcH3K3I (ORCPT + 27 others); Tue, 30 Aug 2016 06:29:08 -0400 Received: from mail-pa0-f45.google.com ([209.85.220.45]:36601 "EHLO mail-pa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757595AbcH3K3C (ORCPT ); Tue, 30 Aug 2016 06:29:02 -0400 Received: by mail-pa0-f45.google.com with SMTP id ci2so6413421pad.3 for ; Tue, 30 Aug 2016 03:29:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=pmTBfTg6xh+gUyI+X7/VB026fGpnf15uSAKmw+w+kw8=; b=FDibnXOWLA7EaTZFL2Nf9do3lWSXRMBMtfmlMMulCydKOaXAP8k8f+xnW2eVjIofFP 5XsT2X4R7Bm+OJ9C0KCOAOjdeWx3w/3HSB4kq9ejUHzbKdFmrSzeSHjo8zXFnRBZVnmp tnMMyEVmj1d5pnZeBJ2YTDqAKmaq8ygHFrZvM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=pmTBfTg6xh+gUyI+X7/VB026fGpnf15uSAKmw+w+kw8=; b=FsmtBw8fpfYyXrRs2/Z7gvmowDPtOITOIluWLdsWGCgZmkV7vApmXwK+64osFECZPJ 0VJsDyP/VuGfLfDzhElSXOa7cAVJRCgOEQ6NTh8l2s+aY36IO35ZVGpsbmenjoWfuueh bD2F4Ryj08whjcptjuo3ENpLlQGuYVXmno3Se/K9ERRr1EPNRr7+LXjSXXHpeSZJE3iV 2xd/spxtoJAJYnXbq/kALd2tyLsAG8ITrzlEbmInuSW+kYbFBg/+FGy1TL+9SSFzCsFt 3ttltOvUTkszePSegMU2LRpBBysjDGfLgkP0uW9pEHiRAGlDMGtV9DuczfTDTCCgHl2o eJQA== X-Gm-Message-State: AE9vXwNX7QmG13svbLTo6hPsXqZjaMr20UVoBsgJnTyhe2Qq6JRKV+vHKZ1prFN0NLSgSO4M X-Received: by 10.66.52.47 with SMTP id q15mr4761586pao.67.1472552941382; Tue, 30 Aug 2016 03:29:01 -0700 (PDT) Received: from blr-ubuntu-59.ap.qualcomm.com ([202.46.23.61]) by smtp.gmail.com with ESMTPSA id k78sm55893307pfa.78.2016.08.30.03.28.58 (version=TLS1_1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 30 Aug 2016 03:29:00 -0700 (PDT) From: Binoy Jayan To: "Steven Rostedt (Red Hat)" Cc: Ingo Molnar , Daniel Wagner , Arnd Bergmann , linux-kernel@vger.kernel.org, Masami , Binoy Jayan Subject: [PATCH v4 2/3] tracing: Add trace_irqsoff tracepoints Date: Tue, 30 Aug 2016 15:58:43 +0530 Message-Id: <1472552924-22297-3-git-send-email-binoy.jayan@linaro.org> X-Mailer: git-send-email 1.8.2.1 In-Reply-To: <1472552924-22297-1-git-send-email-binoy.jayan@linaro.org> References: <1472552924-22297-1-git-send-email-binoy.jayan@linaro.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This work is based on work by Daniel Wagner. A few tracepoints are added at the end of the critical section. With the hist trigger in place, the hist trigger plots may be generated, with per-cpu breakdown of events captured. It is based on linux kernel's event infrastructure. The following filter(s) may be used 'hist:key=latency.log2:val=hitcount:sort=latency' 'hist:key=ltype,latency:val=hitcount:sort=latency if cpu==1' 'hist:key=ltype:val=latency:sort=ltype if ltype==0 && cpu==2' Where ltype is 0: IRQSOFF latency 1: PREEMPTOFF Latency 2: Critical Timings This captures only the latencies introduced by disabled irqs and preemption. Additional per process data has to be captured to calculate the effective latencies introduced for individual processes. Initial work - latency.patch [1] https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit/?h=v3.14-rt-rebase&id=56d50cc34943bbba12b8c5942ee1ae3b29f73acb Signed-off-by: Binoy Jayan --- include/trace/events/latency.h | 35 +++++++++++++++++++++++++++++++++++ kernel/trace/trace_irqsoff.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 77 insertions(+) create mode 100644 include/trace/events/latency.h -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project diff --git a/include/trace/events/latency.h b/include/trace/events/latency.h new file mode 100644 index 0000000..e89be12 --- /dev/null +++ b/include/trace/events/latency.h @@ -0,0 +1,35 @@ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM latency + +#if !defined(_TRACE_HIST_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_HIST_H + +#include + +DECLARE_EVENT_CLASS(latency_template, + TP_PROTO(int ltype, cycles_t latency), + + TP_ARGS(ltype, latency), + + TP_STRUCT__entry( + __field(int, ltype) + __field(cycles_t, latency) + ), + + TP_fast_assign( + __entry->ltype = ltype; + __entry->latency = latency; + ), + + TP_printk("ltype=%d, latency=%lu", + __entry->ltype, (unsigned long) __entry->latency) +); + +DEFINE_EVENT(latency_template, latency_preempt, + TP_PROTO(int ltype, cycles_t latency), + TP_ARGS(ltype, latency)); + +#endif /* _TRACE_HIST_H */ + +/* This part must be outside protection */ +#include diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index 03cdff8..f70ab69 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -13,13 +13,26 @@ #include #include #include +#include +#include #include "trace.h" +#define CREATE_TRACE_POINTS +#include + +enum latency_type { + LT_IRQ, + LT_PREEMPT, + LT_CRITTIME, + LT_MAX +}; + static struct trace_array *irqsoff_trace __read_mostly; static int tracer_enabled __read_mostly; static DEFINE_PER_CPU(int, tracing_cpu); +static DEFINE_PER_CPU(cycle_t, lat_ts[LT_MAX]); static DEFINE_RAW_SPINLOCK(max_trace_lock); @@ -419,9 +432,23 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip) atomic_dec(&data->disabled); } +static inline void trace_latency_preempt_mark_ts(enum latency_type ltype) +{ + this_cpu_write(lat_ts[ltype], (cycle_t) trace_clock_local()); +} + +static inline void latency_trace(enum latency_type type) +{ + trace_latency_preempt(type, + (cycle_t) trace_clock_local() - this_cpu_read(lat_ts[type])); +} + /* start and stop critical timings used to for stoppage (in idle) */ void start_critical_timings(void) { + if (trace_latency_preempt_enabled()) + trace_latency_preempt_mark_ts(LT_CRITTIME); + if (preempt_trace() || irq_trace()) start_critical_timing(CALLER_ADDR0, CALLER_ADDR1); } @@ -431,6 +458,9 @@ void stop_critical_timings(void) { if (preempt_trace() || irq_trace()) stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1); + + if (trace_latency_preempt_enabled()) + latency_trace(LT_CRITTIME); } EXPORT_SYMBOL_GPL(stop_critical_timings); @@ -438,6 +468,9 @@ EXPORT_SYMBOL_GPL(stop_critical_timings); #ifdef CONFIG_PROVE_LOCKING void time_hardirqs_on(unsigned long a0, unsigned long a1) { + if (trace_latency_preempt_enabled()) + latency_trace(LT_IRQ); + if (!preempt_trace() && irq_trace()) stop_critical_timing(a0, a1); } @@ -446,6 +479,9 @@ void time_hardirqs_off(unsigned long a0, unsigned long a1) { if (!preempt_trace() && irq_trace()) start_critical_timing(a0, a1); + + if (trace_latency_preempt_enabled()) + trace_latency_preempt_mark_ts(LT_IRQ); } #else /* !CONFIG_PROVE_LOCKING */ @@ -503,6 +539,9 @@ EXPORT_SYMBOL(trace_hardirqs_off_caller); #ifdef CONFIG_PREEMPT_TRACER void trace_preempt_on(unsigned long a0, unsigned long a1) { + if (trace_latency_preempt_enabled()) + latency_trace(LT_PREEMPT); + if (preempt_trace() && !irq_trace()) stop_critical_timing(a0, a1); } @@ -511,6 +550,9 @@ void trace_preempt_off(unsigned long a0, unsigned long a1) { if (preempt_trace() && !irq_trace()) start_critical_timing(a0, a1); + + if (trace_latency_preempt_enabled()) + trace_latency_preempt_mark_ts(LT_PREEMPT); } #endif /* CONFIG_PREEMPT_TRACER */