From patchwork Tue Apr 16 09:48:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anju T Sudhakar X-Patchwork-Id: 1086172 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 44k0wT1kzfz9s00 for ; Tue, 16 Apr 2019 19:50:17 +1000 (AEST) 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 44k0wT0SmPzDqHP for ; Tue, 16 Apr 2019 19:50:17 +1000 (AEST) 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=148.163.156.1; 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 (mx0a-001b2d01.pphosted.com [148.163.156.1]) (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 44k0tg5WYDzDq61 for ; Tue, 16 Apr 2019 19:48:43 +1000 (AEST) Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x3G9ie2M109096 for ; Tue, 16 Apr 2019 05:48:42 -0400 Received: from e06smtp02.uk.ibm.com (e06smtp02.uk.ibm.com [195.75.94.98]) by mx0a-001b2d01.pphosted.com with ESMTP id 2rwcb5145f-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 16 Apr 2019 05:48:41 -0400 Received: from localhost by e06smtp02.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) Tue, 16 Apr 2019 10:48:37 +0100 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x3G9maPK49545470 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 16 Apr 2019 09:48:36 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 722994C05C; Tue, 16 Apr 2019 09:48:36 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5BE0E4C062; Tue, 16 Apr 2019 09:48:35 +0000 (GMT) Received: from localhost.localdomain.com (unknown [9.145.144.43]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 16 Apr 2019 09:48:35 +0000 (GMT) From: Anju T Sudhakar To: mpe@ellerman.id.au Subject: [PATCH v4 0/5] powerpc/perf: IMC trace-mode support Date: Tue, 16 Apr 2019 15:18:26 +0530 X-Mailer: git-send-email 2.17.2 X-TM-AS-GCONF: 00 x-cbid: 19041609-0008-0000-0000-000002DA5835 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19041609-0009-0000-0000-000022468FD1 Message-Id: <20190416094831.7264-1-anju@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-04-16_03:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=860 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904160067 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, linux-kernel@vger.kernel.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, the 64 bit trace scom value is initialized with the event information. The CPMC*SEL and CPMC_LOAD in the trace scom, specifies the event to be monitored and the sampling duration. On each overflow in the CPMC*SEL, hardware snapshots the program counter along with event counts and writes into memory pointed by LDBAR. LDBAR has bits to indicate whether hardware is configured for accumulation or trace mode. Currently the event monitored for trace-mode is fixed as cycle. 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 at 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 event counts 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. OPAL support for IMC trace mode is already upstream. * 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 ---------------------- PMI interrupt handling is avoided, since IMC trace mode snapshots the program counter and update to the memory. And this also provide a way for the operating system to do instruction sampling in real time without PMI(Performance Monitoring Interrupts) processing overhead. Performance data using 'perf top' with and without trace-imc event: PMI interrupts count when `perf top` command is executed without trace-imc event. # 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 (executed 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 v3 -> v4: * trace_imc_refc is introduced. So that even if, core-imc is disabled, trace-imc can be used. * trace_imc_pmu_sched_task is removed and opal start/stop is invoked in trace_imc_event_add/del function. 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 | 340 +++++++++++++++++++++- arch/powerpc/platforms/powernv/opal-imc.c | 3 + include/linux/cpuhotplug.h | 1 + 5 files changed, 372 insertions(+), 12 deletions(-)