From patchwork Fri Dec 14 09:11:17 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anju T Sudhakar X-Patchwork-Id: 1013404 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 43GPwz11gmz9s0t for ; Fri, 14 Dec 2018 20:13:39 +1100 (AEDT) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.vnet.ibm.com Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 43GPwy6WMNzDrL1 for ; Fri, 14 Dec 2018 20:13:38 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.vnet.ibm.com X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=none (mailfrom) smtp.mailfrom=linux.vnet.ibm.com (client-ip=148.163.158.5; helo=mx0a-001b2d01.pphosted.com; envelope-from=anju@linux.vnet.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.vnet.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 43GPtY0cfyzDrD2 for ; Fri, 14 Dec 2018 20:11:32 +1100 (AEDT) Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wBE992WX041445 for ; Fri, 14 Dec 2018 04:11:28 -0500 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0b-001b2d01.pphosted.com with ESMTP id 2pc9c2rtc2-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 14 Dec 2018 04:11:28 -0500 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 14 Dec 2018 09:11:25 -0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id wBE9BOWa57671860 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 14 Dec 2018 09:11:24 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 065794C058; Fri, 14 Dec 2018 09:11:24 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0ADAB4C04A; Fri, 14 Dec 2018 09:11:23 +0000 (GMT) Received: from localhost.in.ibm.com (unknown [9.124.31.22]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 14 Dec 2018 09:11:22 +0000 (GMT) From: Anju T Sudhakar To: mpe@ellerman.id.au, linux-kernel@vger.kernel.org Subject: [PATCH v2 0/5] powerpc/perf: IMC trace-mode support Date: Fri, 14 Dec 2018 14:41:17 +0530 X-Mailer: git-send-email 2.17.1 X-TM-AS-GCONF: 00 x-cbid: 18121409-4275-0000-0000-000002F0623B X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18121409-4276-0000-0000-000037FD9190 Message-Id: <20181214091122.20992-1-anju@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2018-12-14_04:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=861 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1812140085 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: maddy@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, anju@linux.vnet.ibm.com Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" IMC (In-Memory collection counters) is a hardware monitoring facility that collects large number of hardware performance events. POWER9 support two modes for IMC which are the Accumulation mode and Trace mode. In Accumulation mode, event counts are accumulated in system Memory. Hypervisor then reads the posted counts periodically or when requested. In IMC Trace mode, event counted is fixed for cycles and on each overflow, hardware snapshots the program counter along with other details and writes into memory pointed by LDBAR(ring buffer memory, hardware wraps around). LDBAR has bit which indicates the IMC trace-mode. Trace-IMC Implementation: -------------------------- To enable trace-imc, we need to * Add trace node in the DTS file for power9, so that the new trace node can be discovered by the kernel. Information included in the DTS file are as follows, (a snippet from the ima-catalog) TRACE_IMC: trace-events { #address-cells = <0x1>; #size-cells = <0x1>; event@10200000 { event-name = "cycles" ; reg = <0x10200000 0x8>; desc = "Reference cycles" ; }; }; trace@0 { compatible = "ibm,imc-counters"; events-prefix = "trace_"; reg = <0x0 0x8>; events = < &TRACE_IMC >; type = <0x2>; size = <0x40000>; }; OP-BUILD changes needed to include the "trace node" is already pulled in to the ima-catalog repo. ps://github.com/open-power/op-build/commit/d3e75dc26d1283d7d5eb444bff1ec9e40d5dfc07 * Enchance the opal_imc_counters_* calls to support this new trace mode in imc. Add support to initialize the trace-mode scom. TRACE_IMC_SCOM bit representation: 0:1 : SAMPSEL 2:33 : CPMC_LOAD 34:40 : CPMC1SEL 41:47 : CPMC2SEL 48:50 : BUFFERSIZE 51:63 : RESERVED CPMC_LOAD contains the sampling duration. SAMPSEL and CPMC*SEL determines the event to count. BUFFRSIZE indicates the memory range. On each overflow, hardware snapshots program counter along with other details and update the memory and reloads the CMPC_LOAD value for the next sampling duration. IMC hardware does not support exceptions, so it quietly wraps around if memory buffer reaches the end. Link to the skiboot patches to enhance the opal_imc_counters_* calls: https://lists.ozlabs.org/pipermail/skiboot/2018-December/012878.html https://lists.ozlabs.org/pipermail/skiboot/2018-December/012879.html https://lists.ozlabs.org/pipermail/skiboot/2018-December/012882.html https://lists.ozlabs.org/pipermail/skiboot/2018-December/012880.html https://lists.ozlabs.org/pipermail/skiboot/2018-December/012881.html https://lists.ozlabs.org/pipermail/skiboot/2018-December/012883.html * Set LDBAR spr to enable imc-trace mode. LDBAR Layout: 0 : Enable/Disable 1 : 0 -> Accumulation Mode 1 -> Trace Mode 2:3 : Reserved 4-6 : PB scope 7 : Reserved 8:50 : Counter Address 51:63 : Reserved ---------------- Key benefit of imc trace-mode is, each sample record contains the address pointer along with other information. So that, we can profile the IP without interrupting the application. Performance data using 'perf top' with and without trace-imc event: When the application is monitored with trace-imc event, we dont take any PMI interrupts. PMI interrupts count when `perf top` command is executed without trac-imc event. # perf top 12.53% [kernel] [k] arch_cpu_idle 11.32% [kernel] [k] rcu_idle_enter 10.76% [kernel] [k] __next_timer_interrupt 9.49% [kernel] [k] find_next_bit 8.06% [kernel] [k] rcu_dynticks_eqs_exit 7.82% [kernel] [k] do_idle 5.71% [kernel] [k] tick_nohz_idle_stop_tic [-----------------------] # cat /proc/interrupts (a snippet from the output) 9944 1072 804 804 1644 804 1306 804 804 804 804 804 804 804 804 804 1961 1602 804 804 1258 [-----------------------------------------------------------------] 803 803 803 803 803 803 803 803 803 803 803 804 804 804 804 804 804 804 804 804 803 803 803 803 803 803 1306 803 803 Performance monitoring interrupts `perf top` with trace-imc (right after 'perf top' without trace-imc event): # perf top -e trace_imc/trace_cycles/ 12.50% [kernel] [k] arch_cpu_idle 11.81% [kernel] [k] __next_timer_interrupt 11.22% [kernel] [k] rcu_idle_enter 10.25% [kernel] [k] find_next_bit 7.91% [kernel] [k] do_idle 7.69% [kernel] [k] rcu_dynticks_eqs_exit 5.20% [kernel] [k] tick_nohz_idle_stop_tick [-----------------------] # cat /proc/interrupts (a snippet from the output) 9944 1072 804 804 1644 804 1306 804 804 804 804 804 804 804 804 804 1961 1602 804 804 1258 [-----------------------------------------------------------------] 803 803 803 803 803 803 803 803 803 803 804 804 804 804 804 804 804 804 804 804 803 803 803 803 803 803 1306 803 803 Performance monitoring interrupts The PMI interrupts count remains the same. Changelog: From v1 -> v2 -------------- * Added privileged access check for thread-imc and trace-imc Suggestions/comments are welcome. Anju T Sudhakar (4): powerpc/include: Add data structures and macros for IMC trace mode powerpc/perf: Rearrange setting of ldbar for thread-imc powerpc/perf: Trace imc events detection and cpuhotplug powerpc/perf: Trace imc PMU functions Madhavan Srinivasan (1): powerpc/perf: Add privileged access check for thread_imc arch/powerpc/include/asm/imc-pmu.h | 39 +++ arch/powerpc/include/asm/opal-api.h | 1 + arch/powerpc/perf/imc-pmu.c | 297 +++++++++++++++++++++- arch/powerpc/platforms/powernv/opal-imc.c | 3 + include/linux/cpuhotplug.h | 1 + 5 files changed, 330 insertions(+), 11 deletions(-)