From patchwork Thu Oct 10 14:31:50 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adrian Hunter X-Patchwork-Id: 13830316 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 479011E04AB; Thu, 10 Oct 2024 14:34:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.18 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728570859; cv=none; b=ocYG4JSkLxIxRh5QuIGP/YyP4myV6Wv8nlber5nEn0/Pus2ZtU2MbQknqV7ZRikkLHhkusW0pfOkPGBoTWxJCH+3uzjbd+IsvHVJbu3jp71ll+cIRKhCh/Nu1kfywYY1wFpILaQki/+7iI2X1oMCoI2J7ddro0wcJPlgMg4bnKU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728570859; c=relaxed/simple; bh=CNC4Qu4W7jk8/r3gBPZqjjI8XDWlS8w03Hcg6IhAZ+8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PVR8qLYzkMWUZcIcxTBp7riNz6cdLlV50V/h7CxmBuyZs+gqrbQ3vQD+APu8oxxBFMlJjA799IZFfItlyvUB3bI6K8oYpZwzYVXUYsPOejP95FHcOkJswtXxgrjKLGp6q51IMTOBmMaeXaTGTjibFrmpCWG8YgGevtBlkOsOrr4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=hOSMKvdx; arc=none smtp.client-ip=198.175.65.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="hOSMKvdx" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1728570857; x=1760106857; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=CNC4Qu4W7jk8/r3gBPZqjjI8XDWlS8w03Hcg6IhAZ+8=; b=hOSMKvdxKWljasgX3YaFp77oT+3Lnpw608wYCMRRKoIdlwk+S+xAhPOr twUOrM4djbSafcS1DTXVc0y7rdA8EwUma1b6hv9rSxyjIT8rjmgt+WxqM wqUVTZeN9M6DHzYpOsx/jlkj8hrYte/zeBlwZ2u84hVxkprMSwEIWkvfw l1mKDrXGSDfIdgBpps+MJopXjTnOWK2gVDjzWAN+U6CrpQIqHEby9i3Hj L944rhu2yOIuochoIFtudjHXMWi6ZPFCFdRPu9KiryF/cjkRL9zAGFCJ7 NkD8OWOlVWgE2WUy1E69u8RMzPE+kHwIpOHXT0hpFmce/Qpi91OFZmOme Q==; X-CSE-ConnectionGUID: 7biZ8D44RoGDBxt9sOuLTg== X-CSE-MsgGUID: +ngmqCOnSLyOjuHCKGu82Q== X-IronPort-AV: E=McAfee;i="6700,10204,11220"; a="28064472" X-IronPort-AV: E=Sophos;i="6.11,193,1725346800"; d="scan'208";a="28064472" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by orvoesa110.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Oct 2024 07:34:16 -0700 X-CSE-ConnectionGUID: gtV70Yj0SmWU9G/mLjeM8g== X-CSE-MsgGUID: zI1imOQHSJ+hmOvIoVXemw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.11,193,1725346800"; d="scan'208";a="81189581" Received: from ahunter6-mobl1.ger.corp.intel.com (HELO localhost.localdomain) ([10.246.16.81]) by fmviesa004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Oct 2024 07:34:07 -0700 From: Adrian Hunter To: Peter Zijlstra , Sean Christopherson , Paolo Bonzini Cc: Ingo Molnar , Mark Rutland , Alexander Shishkin , Heiko Carstens , Thomas Richter , Hendrik Brueckner , Suzuki K Poulose , Mike Leach , James Clark , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, Yicong Yang , Jonathan Cameron , Will Deacon , Arnaldo Carvalho de Melo , Jiri Olsa , Namhyung Kim , Ian Rogers , Andi Kleen , Thomas Gleixner , Borislav Petkov , Dave Hansen , x86@kernel.org, H Peter Anvin , Kan Liang , Zhenyu Wang , kvm@vger.kernel.org, Shuah Khan , linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH V12 13/14] perf intel-pt: Add documentation for pause / resume Date: Thu, 10 Oct 2024 17:31:50 +0300 Message-ID: <20241010143152.19071-14-adrian.hunter@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241010143152.19071-1-adrian.hunter@intel.com> References: <20241010143152.19071-1-adrian.hunter@intel.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Document the use of aux-action config term and provide a simple example. Signed-off-by: Adrian Hunter Acked-by: Ian Rogers Reviewed-by: Andi Kleen --- Changes in V5: Added more examples tools/perf/Documentation/perf-intel-pt.txt | 108 +++++++++++++++++++++ 1 file changed, 108 insertions(+) diff --git a/tools/perf/Documentation/perf-intel-pt.txt b/tools/perf/Documentation/perf-intel-pt.txt index ad39bf20f862..cc0f37f0fa5a 100644 --- a/tools/perf/Documentation/perf-intel-pt.txt +++ b/tools/perf/Documentation/perf-intel-pt.txt @@ -555,6 +555,9 @@ Support for this feature is indicated by: which contains "1" if the feature is supported and "0" otherwise. +*aux-action=start-paused*:: +Start tracing paused, refer to the section <<_pause_or_resume_tracing,Pause or Resume Tracing>> + config terms on other events ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -570,6 +573,9 @@ and PEBS-via-PT. In those cases, the other events can have config terms below: Used to select PEBS-via-PT, refer to the section <<_pebs_via_intel_pt,PEBS via Intel PT>> +*aux-action*:: + Used to pause or resume tracing, refer to the section + <<_pause_or_resume_tracing,Pause or Resume Tracing>> AUX area sampling option ~~~~~~~~~~~~~~~~~~~~~~~~ @@ -1915,6 +1921,108 @@ For pipe mode, the order of events and timestamps can presumably be messed up. +Pause or Resume Tracing +----------------------- + +With newer Kernels, it is possible to use other selected events to pause +or resume Intel PT tracing. This is configured by using the "aux-action" +config term: + +"aux-action=pause" is used with events that are to pause Intel PT tracing. + +"aux-action=resume" is used with events that are to resume Intel PT tracing. + +"aux-action=start-paused" is used with the Intel PT event to start in a +paused state. + +For example, to trace only the uname system call (sys_newuname) when running the +command line utility uname: + + $ perf record --kcore -e intel_pt/aux-action=start-paused/k,syscalls:sys_enter_newuname/aux-action=resume/,syscalls:sys_exit_newuname/aux-action=pause/ uname + Linux + [ perf record: Woken up 1 times to write data ] + [ perf record: Captured and wrote 0.043 MB perf.data ] + $ perf script --call-trace + uname 30805 [000] 24001.058782799: name: 0x7ffc9c1865b0 + uname 30805 [000] 24001.058784424: psb offs: 0 + uname 30805 [000] 24001.058784424: cbr: 39 freq: 3904 MHz (139%) + uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) debug_smp_processor_id + uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) __x64_sys_newuname + uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) down_read + uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) __cond_resched + uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) preempt_count_add + uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) in_lock_functions + uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) preempt_count_sub + uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) up_read + uname 30805 [000] 24001.058784629: ([kernel.kallsyms]) preempt_count_add + uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) in_lock_functions + uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) preempt_count_sub + uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) _copy_to_user + uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) syscall_exit_to_user_mode + uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) syscall_exit_work + uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) perf_syscall_exit + uname 30805 [000] 24001.058784838: ([kernel.kallsyms]) debug_smp_processor_id + uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_trace_buf_alloc + uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_swevent_get_recursion_context + uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) debug_smp_processor_id + uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) debug_smp_processor_id + uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_tp_event + uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_trace_buf_update + uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) tracing_gen_ctx_irq_test + uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_swevent_event + uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) __perf_event_account_interrupt + uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) __this_cpu_preempt_check + uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_event_output_forward + uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) perf_event_aux_pause + uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) ring_buffer_get + uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) __rcu_read_lock + uname 30805 [000] 24001.058785046: ([kernel.kallsyms]) __rcu_read_unlock + uname 30805 [000] 24001.058785254: ([kernel.kallsyms]) pt_event_stop + uname 30805 [000] 24001.058785254: ([kernel.kallsyms]) debug_smp_processor_id + uname 30805 [000] 24001.058785254: ([kernel.kallsyms]) debug_smp_processor_id + uname 30805 [000] 24001.058785254: ([kernel.kallsyms]) native_write_msr + uname 30805 [000] 24001.058785463: ([kernel.kallsyms]) native_write_msr + uname 30805 [000] 24001.058785639: 0x0 + +The example above uses tracepoints, but any kind of sampled event can be used. + +For example: + + Tracing between arch_cpu_idle_enter() and arch_cpu_idle_exit() using breakpoint events: + + $ sudo cat /proc/kallsyms | sort | grep ' arch_cpu_idle_enter\| arch_cpu_idle_exit' + ffffffffb605bf60 T arch_cpu_idle_enter + ffffffffb614d8a0 W arch_cpu_idle_exit + $ sudo perf record --kcore -a -e intel_pt/aux-action=start-paused/k -e mem:0xffffffffb605bf60:x/aux-action=resume/ -e mem:0xffffffffb614d8a0:x/aux-action=pause/ -- sleep 1 + [ perf record: Woken up 1 times to write data ] + [ perf record: Captured and wrote 1.387 MB perf.data ] + + Tracing __alloc_pages() using kprobes: + + $ sudo perf probe --add '__alloc_pages order' + Added new event: probe:__alloc_pages (on __alloc_pages with order) + $ sudo perf probe --add __alloc_pages%return + Added new event: probe:__alloc_pages__return (on __alloc_pages%return) + $ sudo perf record --kcore -aR -e intel_pt/aux-action=start-paused/k -e probe:__alloc_pages/aux-action=resume/ -e probe:__alloc_pages__return/aux-action=pause/ -- sleep 1 + [ perf record: Woken up 1 times to write data ] + [ perf record: Captured and wrote 1.490 MB perf.data ] + + Tracing starting at main() using a uprobe event: + + $ sudo perf probe -x /usr/bin/uname main + Added new event: probe_uname:main (on main in /usr/bin/uname) + $ sudo perf record -e intel_pt/-aux-action=start-paused/u -e probe_uname:main/aux-action=resume/ -- uname + Linux + [ perf record: Woken up 1 times to write data ] + [ perf record: Captured and wrote 0.031 MB perf.data ] + + Tracing occasionally using cycles events with different periods: + + $ perf record --kcore -a -m,64M -e intel_pt/aux-action=start-paused/k -e cycles/aux-action=pause,period=1000000/Pk -e cycles/aux-action=resume,period=10500000/Pk -- firefox + [ perf record: Woken up 19 times to write data ] + [ perf record: Captured and wrote 16.561 MB perf.data ] + + EXAMPLE -------