From patchwork Tue Oct 22 15:59:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adrian Hunter X-Patchwork-Id: 13845968 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8AE71D2CDFA for ; Tue, 22 Oct 2024 16:40:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=lXCSWO+aZiDuzSZJdG+pgd812IrvsHNHZeHI0n9Ceg0=; b=xk7pMPsD/FCsskrwLYzbq/jrhR H2lhH0wd2l21z9dCP70C2RYPzMN6RSog8D2a5ELVmotBjC9tnSIk3GQ+JXaXQ0VOhh/HkMLmhbMWY vNnEpGDZ6y3ZnvO1segfYwSKoxkghI7Cq5k88Dqgqe1KlM9UriFUdM03Cj8Jm3Qgy9W9oG0pttyHq 3iza+GjHfWJ22T0Bm5LX4PdTwenQtcNKQbYU7zOx+L6OUI0ZMYe1jBSBHywGSjBryCkx8ammadCFC C1RTOtYlXfz2SpNHJH85rcqP6LQkrukGM9uNJ5QzpdqpVSQ5FlIp9GiDUgAdI8lJz4c3SeY39chra gymz/sCg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t3HvF-0000000BV9E-3irU; Tue, 22 Oct 2024 16:39:53 +0000 Received: from mgamail.intel.com ([192.198.163.15]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t3HJh-0000000BM0g-3dgs for linux-arm-kernel@lists.infradead.org; Tue, 22 Oct 2024 16:01:09 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1729612866; x=1761148866; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=CNC4Qu4W7jk8/r3gBPZqjjI8XDWlS8w03Hcg6IhAZ+8=; b=fVQbhOaJTezOhCJOU786Q21oexy9MCGwAVrZb8rSWqwtymN85GAP90Mu Y6ChpSfhWqvmNSH5kmt7LkQODzJyJwsetm6kuJBU9vyWqvGokzSZz6kGY doC4753Q9McHUgOhst4O4SJ+xIR3Ze84UtbBngDfU3hXI/6Oj+AP4tI6f b4FJ5WQSZDJTv+LiibIiwhPuxazZORw4YpQfti0xYtliHmYXADAoJvD1q NFxwA4rIY99U0E5bq0pqqoUYtgNwoa7hQi6XaOvsqtuaoSNRp73lfkrLT WVr9jQfpuZuoNQoqp81/X6CNGtGFkGq9DFoIxnZSNxpCOKKIRi/8mUbgD A==; X-CSE-ConnectionGUID: p8S+EH8nS8m3B5zTi6jmew== X-CSE-MsgGUID: bVsCVTWPTBKsbmjx8vUebw== X-IronPort-AV: E=McAfee;i="6700,10204,11233"; a="29271150" X-IronPort-AV: E=Sophos;i="6.11,223,1725346800"; d="scan'208";a="29271150" Received: from orviesa010.jf.intel.com ([10.64.159.150]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Oct 2024 09:01:05 -0700 X-CSE-ConnectionGUID: ZVxtUs89TTeUxmmEAmAxjQ== X-CSE-MsgGUID: J5KOoMOLQcOD3BIUI2n4kA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.11,223,1725346800"; d="scan'208";a="79858912" Received: from ahunter6-mobl1.ger.corp.intel.com (HELO ahunter-VirtualBox.ger.corp.intel.com) ([10.246.16.81]) by orviesa010-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Oct 2024 09:00:56 -0700 From: Adrian Hunter To: Peter Zijlstra 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 , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: [PATCH V14 10/11] perf intel-pt: Add documentation for pause / resume Date: Tue, 22 Oct 2024 18:59:16 +0300 Message-ID: <20241022155920.17511-11-adrian.hunter@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241022155920.17511-1-adrian.hunter@intel.com> References: <20241022155920.17511-1-adrian.hunter@intel.com> MIME-Version: 1.0 Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241022_090106_108979_EB89241B X-CRM114-Status: GOOD ( 13.66 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 -------