From patchwork Mon Aug 28 06:15:29 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aboorva Devarajan X-Patchwork-Id: 1826603 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256 header.s=pp1 header.b=ZKnTxkUY; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=patchwork.ozlabs.org) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4RZ0gG606vz1yfX for ; Mon, 28 Aug 2023 16:16:10 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256 header.s=pp1 header.b=ZKnTxkUY; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4RZ0gG24Tyz3bXm for ; Mon, 28 Aug 2023 16:16:10 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256 header.s=pp1 header.b=ZKnTxkUY; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=linux.vnet.ibm.com (client-ip=148.163.158.5; helo=mx0b-001b2d01.pphosted.com; envelope-from=aboorvad@linux.vnet.ibm.com; receiver=lists.ozlabs.org) Received: from mx0b-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 4RZ0ft0KVWz2yw0 for ; Mon, 28 Aug 2023 16:15:49 +1000 (AEST) Received: from pps.filterd (m0356516.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 37S5Uqm5008392; Mon, 28 Aug 2023 06:15:39 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=SJmsxuy8ffDRbgP7xPMc8Wg4G9QTOfSbHtC6Ac8HPoE=; b=ZKnTxkUYzHu8kYk60PypmO3LpmLUZ1nx9QFZFKitVkVJ73mLoQ/GECc4RJn7OWhUoUeQ bWAom60uPD6pinYxE5F8vZGHokBZx01V7N/q9ck82sEVsnLXJh16zIsIpl+mUsB68ZVp rXwlblWJmfOsKp/3ZbLCuqS0gDbpNanmoFmzKDyEfbzZ/Biyj2j6WIgZgxPClKBYnyWy acmzhtvLgleGFcW4YV69TI5mIz3WX7jB+jl+GdPtFjgWIleRB3ZjSd5gnL7VXJP4ZTQ/ fJIgMwilgBFhYHPMK+BkWZp90M/4Wfv73FZlVrN6d5OdzZg/lx/Fvg1/sDrPac3eAvBw ng== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3sradxk6vb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 28 Aug 2023 06:15:39 +0000 Received: from m0356516.ppops.net (m0356516.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 37S5Rmdg029860; Mon, 28 Aug 2023 06:15:38 GMT Received: from ppma22.wdc07v.mail.ibm.com (5c.69.3da9.ip4.static.sl-reverse.com [169.61.105.92]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3sradxk6v2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 28 Aug 2023 06:15:38 +0000 Received: from pps.filterd (ppma22.wdc07v.mail.ibm.com [127.0.0.1]) by ppma22.wdc07v.mail.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 37S3mEFV020543; Mon, 28 Aug 2023 06:15:38 GMT Received: from smtprelay02.fra02v.mail.ibm.com ([9.218.2.226]) by ppma22.wdc07v.mail.ibm.com (PPS) with ESMTPS id 3sqv3y0pfu-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 28 Aug 2023 06:15:38 +0000 Received: from smtpav01.fra02v.mail.ibm.com (smtpav01.fra02v.mail.ibm.com [10.20.54.100]) by smtprelay02.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 37S6Fal419530490 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 28 Aug 2023 06:15:36 GMT Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1BBF52004B; Mon, 28 Aug 2023 06:15:36 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DC9B520040; Mon, 28 Aug 2023 06:15:33 +0000 (GMT) Received: from li-34d1fccc-27cd-11b2-a85c-c167793e56f7.in.ibm.com (unknown [9.204.200.131]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 28 Aug 2023 06:15:33 +0000 (GMT) From: Aboorva Devarajan To: aboorvad@linux.vnet.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, rmclure@linux.ibm.com, arnd@arndb.de, joel@jms.id.au, shuah@kernel.org, linux-kselftest@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, pratik.r.sampat@gmail.com Subject: [RFC v2 1/2] powerpc/cpuidle: cpuidle wakeup latency based on IPI and timer events Date: Mon, 28 Aug 2023 11:45:29 +0530 Message-Id: <20230828061530.126588-2-aboorvad@linux.vnet.ibm.com> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20230828061530.126588-1-aboorvad@linux.vnet.ibm.com> References: <20230828061530.126588-1-aboorvad@linux.vnet.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: tkkWs3_9Xj4_adtlLUfKvk--sIABtge7 X-Proofpoint-ORIG-GUID: 1DHP9YcyIDA2chQmbbKLRPa1tk6T8aKq X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.957,Hydra:6.0.601,FMLib:17.11.176.26 definitions=2023-08-28_03,2023-08-25_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 spamscore=0 lowpriorityscore=0 priorityscore=1501 mlxlogscore=999 clxscore=1015 suspectscore=0 malwarescore=0 mlxscore=0 adultscore=0 phishscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2308100000 definitions=main-2308280055 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: sshegde@linux.vnet.ibm.com, srikar@linux.vnet.ibm.com Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: Pratik R. Sampat Introduce a mechanism to fire directed IPIs from a source CPU to a specified target CPU and measure the time incurred on waking up the target CPU in response. Also, introduce a mechanism to queue a hrtimer on a specified CPU and subsequently measure the time taken to wakeup the CPU. Define a simple debugfs interface that allows for adjusting the settings to trigger IPI and timer events on a designated CPU, and to observe the resulting cpuidle wakeup latencies. Signed-off-by: Pratik R. Sampat Signed-off-by: Aboorva Devarajan Reviewed-by: Shrikanth Hegde Reviewed-by: Srikar Dronamraju --- arch/powerpc/Kconfig.debug | 10 ++ arch/powerpc/kernel/Makefile | 1 + arch/powerpc/kernel/test_cpuidle_latency.c | 156 +++++++++++++++++++++ 3 files changed, 167 insertions(+) create mode 100644 arch/powerpc/kernel/test_cpuidle_latency.c diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug index 2a54fadbeaf5..e175fc3028ac 100644 --- a/arch/powerpc/Kconfig.debug +++ b/arch/powerpc/Kconfig.debug @@ -391,3 +391,13 @@ config KASAN_SHADOW_OFFSET default 0xe0000000 if PPC32 default 0xa80e000000000000 if PPC_BOOK3S_64 default 0xa8001c0000000000 if PPC_BOOK3E_64 + +config CPUIDLE_LATENCY_SELFTEST + tristate "Cpuidle latency selftests" + depends on CPU_IDLE + help + Provides a kernel module that run tests using the IPI and + timers to measure cpuidle latency. + + Say M if you want these self tests to build as a module. + Say N if you are unsure. diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index 2919433be355..3205ecbd9d8f 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -87,6 +87,7 @@ obj-$(CONFIG_PPC_WATCHDOG) += watchdog.o obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o obj-$(CONFIG_PPC_DAWR) += dawr.o obj-$(CONFIG_PPC_BOOK3S_64) += cpu_setup_ppc970.o cpu_setup_pa6t.o +obj-$(CONFIG_CPUIDLE_LATENCY_SELFTEST) += test_cpuidle_latency.o obj-$(CONFIG_PPC_BOOK3S_64) += cpu_setup_power.o obj-$(CONFIG_PPC_BOOK3S_64) += mce.o mce_power.o obj-$(CONFIG_PPC_BOOK3E_64) += exceptions-64e.o idle_64e.o diff --git a/arch/powerpc/kernel/test_cpuidle_latency.c b/arch/powerpc/kernel/test_cpuidle_latency.c new file mode 100644 index 000000000000..3c3c119389c1 --- /dev/null +++ b/arch/powerpc/kernel/test_cpuidle_latency.c @@ -0,0 +1,156 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Module-based API test facility for cpuidle latency using IPIs and timers + */ + +#include +#include +#include + +/* + * IPI based wakeup latencies + * Measure time taken for a CPU to wakeup on a IPI sent from another CPU + * The latency measured also includes the latency of sending the IPI + */ +struct latency { + unsigned int src_cpu; + unsigned int dest_cpu; + ktime_t time_start; + ktime_t time_end; + u64 latency_ns; +} ipi_wakeup; + +static void measure_latency(void *info) +{ + struct latency *v; + ktime_t time_diff; + + v = (struct latency *)info; + v->time_end = ktime_get(); + time_diff = ktime_sub(v->time_end, v->time_start); + v->latency_ns = ktime_to_ns(time_diff); +} + +void run_smp_call_function_test(unsigned int cpu) +{ + ipi_wakeup.src_cpu = smp_processor_id(); + ipi_wakeup.dest_cpu = cpu; + ipi_wakeup.time_start = ktime_get(); + smp_call_function_single(cpu, measure_latency, &ipi_wakeup, 1); +} + +/* + * Timer based wakeup latencies + * Measure time taken for a CPU to wakeup on a timer being armed and fired + */ +struct timer_data { + unsigned int src_cpu; + u64 timeout; + ktime_t time_start; + ktime_t time_end; + struct hrtimer timer; + u64 timeout_diff_ns; +} timer_wakeup; + +static enum hrtimer_restart hrtimer_callback(struct hrtimer *hrtimer) +{ + struct timer_data *w; + ktime_t time_diff; + + w = container_of(hrtimer, struct timer_data, timer); + w->time_end = ktime_get(); + + time_diff = ktime_sub(w->time_end, w->time_start); + time_diff = ktime_sub(time_diff, ns_to_ktime(w->timeout)); + w->timeout_diff_ns = ktime_to_ns(time_diff); + return HRTIMER_NORESTART; +} + +static void run_timer_test(unsigned int ns) +{ + hrtimer_init(&timer_wakeup.timer, CLOCK_MONOTONIC, + HRTIMER_MODE_REL); + timer_wakeup.timer.function = hrtimer_callback; + timer_wakeup.src_cpu = smp_processor_id(); + timer_wakeup.timeout = ns; + timer_wakeup.time_start = ktime_get(); + + hrtimer_start(&timer_wakeup.timer, ns_to_ktime(ns), + HRTIMER_MODE_REL_PINNED); +} + +static struct dentry *dir; + +static int cpu_read_op(void *data, u64 *dest_cpu) +{ + *dest_cpu = ipi_wakeup.dest_cpu; + return 0; +} + +/* + * Send a directed IPI from the current CPU (source) to the destination CPU and + * measure the latency on wakeup. + */ +static int cpu_write_op(void *data, u64 value) +{ + run_smp_call_function_test(value); + return 0; +} +DEFINE_SIMPLE_ATTRIBUTE(ipi_ops, cpu_read_op, cpu_write_op, "%llu\n"); + +static int timeout_read_op(void *data, u64 *timeout) +{ + *timeout = timer_wakeup.timeout; + return 0; +} + +/* Queue a hrtimer on a specified desitination CPU and measure the time taken to + * wakeup the CPU. + */ +static int timeout_write_op(void *data, u64 value) +{ + run_timer_test(value); + return 0; +} +DEFINE_SIMPLE_ATTRIBUTE(timeout_ops, timeout_read_op, timeout_write_op, "%llu\n"); + +static int __init latency_init(void) +{ + struct dentry *temp; + + dir = debugfs_create_dir("latency_test", arch_debugfs_dir); + if (!dir) { + pr_alert("latency_test: failed to create /sys/kernel/debug/powerpc/latency_test\n"); + return -1; + } + temp = debugfs_create_file("ipi_cpu_dest", 0644, dir, NULL, &ipi_ops); + if (!temp) { + pr_alert("latency_test: failed to create /sys/kernel/debug/powerpc/ipi_cpu_dest\n"); + return -1; + } + debugfs_create_u64("ipi_latency_ns", 0444, dir, &ipi_wakeup.latency_ns); + debugfs_create_u32("ipi_cpu_src", 0444, dir, &ipi_wakeup.src_cpu); + + temp = debugfs_create_file("timeout_expected_ns", 0644, dir, NULL, &timeout_ops); + if (!temp) { + pr_alert("latency_test: failed to create /sys/kernel/debug/powerpc/timeout_expected_ns\n"); + return -1; + } + debugfs_create_u64("timeout_diff_ns", 0444, dir, &timer_wakeup.timeout_diff_ns); + debugfs_create_u32("timeout_cpu_src", 0444, dir, &timer_wakeup.src_cpu); + pr_info("Latency Test module loaded\n"); + return 0; +} + +static void __exit latency_cleanup(void) +{ + pr_info("Cleaning up Latency Test module.\n"); + debugfs_remove_recursive(dir); +} + +module_init(latency_init); +module_exit(latency_cleanup); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("IBM Corporation"); +MODULE_DESCRIPTION("Measuring idle latency for IPIs and Timers"); From patchwork Mon Aug 28 06:15:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aboorva Devarajan X-Patchwork-Id: 1826606 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256 header.s=pp1 header.b=rt/4nlwY; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=112.213.38.117; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=patchwork.ozlabs.org) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4RZ0jD3N38z1yfX for ; Mon, 28 Aug 2023 16:17:52 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256 header.s=pp1 header.b=rt/4nlwY; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4RZ0j84T06z3c1W for ; Mon, 28 Aug 2023 16:17:48 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256 header.s=pp1 header.b=rt/4nlwY; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=linux.vnet.ibm.com (client-ip=148.163.156.1; helo=mx0a-001b2d01.pphosted.com; envelope-from=aboorvad@linux.vnet.ibm.com; receiver=lists.ozlabs.org) 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 4RZ0fy1cQsz2ymM for ; Mon, 28 Aug 2023 16:15:54 +1000 (AEST) Received: from pps.filterd (m0353728.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 37S5ohm3021832; Mon, 28 Aug 2023 06:15:43 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=f5vYyEM6sFjbjkcD2j1OT450eJyBoOZeLtxrAJF1Ubk=; b=rt/4nlwYgrc5AWc7tOwl8uD5B/4LkULOyXG0o4Z/jDfQgY7d10IlC8yi/g3CT+4W8U7i JfBqbhtQSQAKJMliBiHyKbpBSBpnYMFuBT+9CY3vhz9+MkPb1sMW0LXEYS4uj7O6PClO cm7/LoEfp/G/1AD38utHJUeRJQJP4uNDjhD6ryDY5Wso8hvcp4PQRPta/CVJVes2Th8q /ZRy+efjxDNtXTydGdz706oY1k88T4MGT0D0bE9tzCesi0ADxz/0/TsJgyCXpLErsv80 E+uNd4IvmmGQCVNGzW8W5FXPsn3ICuvu76p4drQaEzSkME/zHeYQrWmh4WxdjUUKSDnE qQ== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3sr64rpkkh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 28 Aug 2023 06:15:42 +0000 Received: from m0353728.ppops.net (m0353728.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 37S5k5Me005797; Mon, 28 Aug 2023 06:15:42 GMT Received: from ppma23.wdc07v.mail.ibm.com (5d.69.3da9.ip4.static.sl-reverse.com [169.61.105.93]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3sr64rpkk6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 28 Aug 2023 06:15:42 +0000 Received: from pps.filterd (ppma23.wdc07v.mail.ibm.com [127.0.0.1]) by ppma23.wdc07v.mail.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 37S50TVZ009903; Mon, 28 Aug 2023 06:15:41 GMT Received: from smtprelay06.fra02v.mail.ibm.com ([9.218.2.230]) by ppma23.wdc07v.mail.ibm.com (PPS) with ESMTPS id 3sqw7k0a9d-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 28 Aug 2023 06:15:40 +0000 Received: from smtpav01.fra02v.mail.ibm.com (smtpav01.fra02v.mail.ibm.com [10.20.54.100]) by smtprelay06.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 37S6Fcpi19595998 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 28 Aug 2023 06:15:38 GMT Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A18FA2004E; Mon, 28 Aug 2023 06:15:38 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6348520040; Mon, 28 Aug 2023 06:15:36 +0000 (GMT) Received: from li-34d1fccc-27cd-11b2-a85c-c167793e56f7.in.ibm.com (unknown [9.204.200.131]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 28 Aug 2023 06:15:36 +0000 (GMT) From: Aboorva Devarajan To: aboorvad@linux.vnet.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, rmclure@linux.ibm.com, arnd@arndb.de, joel@jms.id.au, shuah@kernel.org, linux-kselftest@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, pratik.r.sampat@gmail.com Subject: [RFC v2 2/2] powerpc/selftest: Add support for cpuidle latency measurement Date: Mon, 28 Aug 2023 11:45:30 +0530 Message-Id: <20230828061530.126588-3-aboorvad@linux.vnet.ibm.com> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20230828061530.126588-1-aboorvad@linux.vnet.ibm.com> References: <20230828061530.126588-1-aboorvad@linux.vnet.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: LWCuxF9UqkzygDbG23oiUdQMjhX4UCrp X-Proofpoint-ORIG-GUID: 17r0P8jBrsz8TlYmdnK69mqhhzNVSLeI X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.957,Hydra:6.0.601,FMLib:17.11.176.26 definitions=2023-08-28_03,2023-08-25_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 lowpriorityscore=0 priorityscore=1501 mlxlogscore=999 impostorscore=0 mlxscore=0 adultscore=0 spamscore=0 suspectscore=0 clxscore=1015 bulkscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2308100000 definitions=main-2308280055 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: sshegde@linux.vnet.ibm.com, srikar@linux.vnet.ibm.com Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: Pratik R. Sampat The cpuidle latency selftest provides support to systematically extract, analyse and present IPI and timer based wakeup latencies for each CPU and each idle state available on the system. The selftest leverages test_cpuidle_latency module's debugfs interface to interact and extract latency information from the kernel. The selftest inserts the module if already not inserted, disables all the idle states and enables them one by one testing the following: 1. Keeping source CPU constant, iterate through all the cores and pick a single CPU for each core measuring IPI latency for baseline (CPU is busy with cat /dev/random > /dev/null workload) and then when the CPU is idle. 2. Iterating through all the CPU cores and selecting one CPU for each core, then, the expected timer durations to be equivalent to the residency of the deepest idle state enabled is sent to the selected target CPU, then the difference between the expected timer duration and the time of wakeup is determined. To run this test specifically: $ sudo make -C tools/testing/selftests \ TARGETS="powerpc/cpuidle_latency" run_tests There are a few optional arguments too that the script can take [-h ] [-i ] [-m ] [-s ] [-o ] [-v (run on all cpus)] Default Output location in: tools/testing/selftests/powerpc/cpuidle_latency/cpuidle_latency.log To run the test without re-compiling: $ cd tools/testing/selftest/powerpc/cpuidle_latency/ $ sudo ./cpuidle_latency.sh Signed-off-by: Pratik R. Sampat Signed-off-by: Aboorva Devarajan Reviewed-by: Shrikanth Hegde --- tools/testing/selftests/powerpc/Makefile | 1 + .../powerpc/cpuidle_latency/.gitignore | 2 + .../powerpc/cpuidle_latency/Makefile | 6 + .../cpuidle_latency/cpuidle_latency.sh | 443 ++++++++++++++++++ .../powerpc/cpuidle_latency/settings | 1 + 5 files changed, 453 insertions(+) create mode 100644 tools/testing/selftests/powerpc/cpuidle_latency/.gitignore create mode 100644 tools/testing/selftests/powerpc/cpuidle_latency/Makefile create mode 100755 tools/testing/selftests/powerpc/cpuidle_latency/cpuidle_latency.sh create mode 100644 tools/testing/selftests/powerpc/cpuidle_latency/settings diff --git a/tools/testing/selftests/powerpc/Makefile b/tools/testing/selftests/powerpc/Makefile index 49f2ad1793fd..efac7270ce1f 100644 --- a/tools/testing/selftests/powerpc/Makefile +++ b/tools/testing/selftests/powerpc/Makefile @@ -17,6 +17,7 @@ SUB_DIRS = alignment \ benchmarks \ cache_shape \ copyloops \ + cpuidle_latency \ dexcr \ dscr \ mm \ diff --git a/tools/testing/selftests/powerpc/cpuidle_latency/.gitignore b/tools/testing/selftests/powerpc/cpuidle_latency/.gitignore new file mode 100644 index 000000000000..987f8852dc59 --- /dev/null +++ b/tools/testing/selftests/powerpc/cpuidle_latency/.gitignore @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +cpuidle_latency.log diff --git a/tools/testing/selftests/powerpc/cpuidle_latency/Makefile b/tools/testing/selftests/powerpc/cpuidle_latency/Makefile new file mode 100644 index 000000000000..04492b6d2582 --- /dev/null +++ b/tools/testing/selftests/powerpc/cpuidle_latency/Makefile @@ -0,0 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0 +all: + +TEST_PROGS := cpuidle_latency.sh + +include ../../lib.mk diff --git a/tools/testing/selftests/powerpc/cpuidle_latency/cpuidle_latency.sh b/tools/testing/selftests/powerpc/cpuidle_latency/cpuidle_latency.sh new file mode 100755 index 000000000000..f7b7a9dc2e08 --- /dev/null +++ b/tools/testing/selftests/powerpc/cpuidle_latency/cpuidle_latency.sh @@ -0,0 +1,443 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# CPU-Idle latency selftest enables systematic retrieval and presentation +# of IPI and timer-triggered wake-up latencies for every CPU and available +# system idle state by leveraging the test_cpuidle_latency module. +# +# Author: Pratik R. Sampat +# Author: Aboorva Devarajan + +DISABLE=1 +ENABLE=0 + +LOG=cpuidle_latency.log +MODULE=/lib/modules/$(uname -r)/kernel/arch/powerpc/kernel/test_cpuidle_latency.ko + +# Kselftest framework requirement - SKIP code is 4. +ksft_skip=4 +exit_status=0 + +RUN_TIMER_TEST=1 +TIMEOUT=1000000 +VERBOSE=0 + +IPI_SRC_CPU=0 + +helpme() { + printf "Usage: %s [-h] [-todg args] + [-h ] + [-s (default: 0)] + [-m ] + [-o ] + [-v (execute test across all CPU threads)] + [-i ] + \n" "$0" + exit 2 +} + +cpu_is_online() { + local cpu=$1 + if [ ! -f "/sys/devices/system/cpu/cpu$cpu/online" ]; then + printf "CPU %s: file not found: /sys/devices/system/cpu/cpu%s/online" "$cpu" "$cpu" + return 0 + fi + status=$(cat /sys/devices/system/cpu/cpu"$cpu"/online) + return "$status" +} + +check_valid_cpu() { + local cpu="$1" + local cpu_count + + cpu_count="$(nproc)" # Get the number of CPUs on the system + + if [[ "$cpu" =~ ^[0-9]+$ ]]; then + if ((cpu >= 0 && cpu < cpu_count)); then + cpu_is_online "$cpu" + online_status=$? + if [ "$online_status" -eq "1" ]; then + return 1 + else + printf "CPU %s is offline." "$cpu" + return 0 + fi + fi + fi + return 0 +} + +parse_arguments() { + while getopts ht:m:s:o:vt:it: arg; do + case $arg in + h) # --help + helpme + ;; + m) # --mod-file + MODULE=$OPTARG + ;; + s) # + IPI_SRC_CPU=$OPTARG + check_valid_cpu "$IPI_SRC_CPU" + cpu_status=$? + if [ "$cpu_status" == "0" ]; then + printf "%s is an invalid CPU. Exiting.." "$IPI_SRC_CPU" + exit + fi + ;; + o) # output log files + LOG=$OPTARG + ;; + v) # verbose mode - execute tests across all CPU threads + VERBOSE=1 + ;; + i) # run timer tests + RUN_TIMER_TEST=1 + ;; + \?) + helpme + ;; + esac + done +} + +ins_mod() { + debugfs_file=/sys/kernel/debug/powerpc/latency_test/ipi_latency_ns + # Check if the module is already loaded + if [ -f "$debugfs_file" ]; then + printf "Module %s already loaded\n\n" "$MODULE" + return 0 + fi + # Try to load the module + if [ ! -f "$MODULE" ]; then + printf "%s module does not exist. Exiting\n" "$MODULE" + exit $ksft_skip + fi + printf "Inserting %s module\n\n" "$MODULE" + insmod "$MODULE" + if [ $? != 0 ]; then + printf "Insmod %s failed\n" "$MODULE" + exit $ksft_skip + fi +} + +compute_average() { + arr=("$@") + sum=0 + size=${#arr[@]} + if [ "$size" == 0 ]; then + avg=0 + return 1 + fi + for i in "${arr[@]}"; do + sum=$((sum + i)) + done + avg=$((sum / size)) +} + +# Perform operation on each CPU for the given state +# $1 - Operation: enable (0) / disable (1) +# $2 - State to enable +op_state() { + for ((cpu = 0; cpu < NUM_CPUS; cpu++)); do + cpu_is_online "$cpu" + local cpu_status=$? + if [ "$cpu_status" == 0 ]; then + continue + fi + echo "$1" >/sys/devices/system/cpu/cpu"$cpu"/cpuidle/state"$2"/disable + done +} + +cpuidle_enable_state() { + state=$1 + op_state "$ENABLE" "$state" +} + +cpuidle_disable_state() { + state=$1 + op_state "$DISABLE" "$state" +} + +# Enable/Disable all stop states for all CPUs +# $1 - Operation: enable (0) / disable (1) +op_cpuidle() { + for ((state = 0; state < NUM_STATES; state++)); do + op_state "$1" "$state" + done +} + +extract_state_information() { + for ((state = 0; state < NUM_STATES; state++)); do + state_name=$(cat /sys/devices/system/cpu/cpu"$IPI_SRC_CPU"/cpuidle/state"$state"/name) + state_name_arr+=("$state_name") + done +} + +# Extract latency in microseconds and convert to nanoseconds +extract_latency() { + for ((state = 0; state < NUM_STATES; state++)); do + latency=$(($(cat /sys/devices/system/cpu/cpu"$IPI_SRC_CPU"/cpuidle/state"$state"/latency) * 1000)) + latency_arr+=("$latency") + done +} + +# Simple linear search in an array +# $1 - Element to search for +# $2 - Array +element_in() { + local item="$1" + shift + for element in "$@"; do + if [ "$element" == "$item" ]; then + return 0 + fi + done + return 1 +} + +# Parse and return a cpuset with ","(individual) and "-" (range) of CPUs +# $1 - cpuset string +parse_cpuset() { + echo "$1" | awk '/-/{for (i=$1; i<=$2; i++)printf "%s%s",i,ORS;next} 1' RS=, FS=- +} + +extract_core_information() { + declare -a thread_arr + for ((cpu = 0; cpu < NUM_CPUS; cpu++)); do + cpu_is_online "$cpu" + local cpu_status=$? + if [ "$cpu_status" == 0 ]; then + continue + fi + + siblings=$(cat /sys/devices/system/cpu/cpu"$cpu"/topology/thread_siblings_list) + sib_arr=() + + for c in $(parse_cpuset "$siblings"); do + sib_arr+=("$c") + done + + if [ "$VERBOSE" == 1 ]; then + core_arr+=("$cpu") + continue + fi + element_in "${sib_arr[0]}" "${thread_arr[@]}" + if [ $? == 0 ]; then + continue + fi + core_arr+=("${sib_arr[0]}") + + for thread in "${sib_arr[@]}"; do + thread_arr+=("$thread") + done + done + + src_siblings=$(cat /sys/devices/system/cpu/cpu"$IPI_SRC_CPU"/topology/thread_siblings_list) + for c in $(parse_cpuset "$src_siblings"); do + first_core_arr+=("$c") + done +} + +# Run the IPI test +# $1 run for baseline - busy cpu or regular environment +# $2 destination cpu +ipi_test_once() { + dest_cpu=$2 + if [ "$1" = "baseline" ]; then + # Keep the CPU busy + taskset -c "$dest_cpu" cat /dev/random >/dev/null & + task_pid=$! + # Wait for the workload to achieve 100% CPU usage + sleep 1 + fi + taskset -c "$IPI_SRC_CPU" echo "$dest_cpu" >/sys/kernel/debug/powerpc/latency_test/ipi_cpu_dest + ipi_latency=$(cat /sys/kernel/debug/powerpc/latency_test/ipi_latency_ns) + src_cpu=$(cat /sys/kernel/debug/powerpc/latency_test/ipi_cpu_src) + if [ "$1" = "baseline" ]; then + kill "$task_pid" + wait "$task_pid" 2>/dev/null + fi +} + +# Incrementally enable idle states one by one and compute the latency +run_ipi_tests() { + extract_latency + # Disable idle states for CPUs + op_cpuidle "$DISABLE" + + declare -a avg_arr + printf "...IPI Latency Test...\n" | tee -a "$LOG" + + printf "...Baseline IPI Latency measurement: CPU Busy...\n" >>"$LOG" + printf "%s %10s %12s\n" "SRC_CPU" "DEST_CPU" "IPI_Latency(ns)" >>"$LOG" + for cpu in "${core_arr[@]}"; do + cpu_is_online "$cpu" + local cpu_status=$? + if [ "$cpu_status" == 0 ]; then + continue + fi + ipi_test_once "baseline" "$cpu" + printf "%-3s %10s %12s\n" "$src_cpu" "$cpu" "$ipi_latency" >>"$LOG" + # Skip computing latency average from the source CPU to avoid bias + element_in "$cpu" "${first_core_arr[@]}" + if [ $? == 0 ]; then + continue + fi + avg_arr+=("$ipi_latency") + done + compute_average "${avg_arr[@]}" + printf "Baseline Avg IPI latency(ns): %s\n" "$avg" | tee -a "$LOG" + + for ((state = 0; state < NUM_STATES; state++)); do + unset avg_arr + printf "...Enabling state: %s...\n" "${state_name_arr[$state]}" >>"$LOG" + cpuidle_enable_state $state + printf "%s %10s %12s\n" "SRC_CPU" "DEST_CPU" "IPI_Latency(ns)" >>"$LOG" + for cpu in "${core_arr[@]}"; do + cpu_is_online "$cpu" + local cpu_status=$? + if [ "$cpu_status" == 0 ]; then + continue + fi + # Running IPI test and logging results + sleep 1 + ipi_test_once "test" "$cpu" + printf "%-3s %10s %12s\n" "$src_cpu" "$cpu" "$ipi_latency" >>"$LOG" + # Skip computing latency average from the source CPU to avoid bias + element_in "$cpu" "${first_core_arr[@]}" + if [ $? == 0 ]; then + continue + fi + avg_arr+=("$ipi_latency") + done + + compute_average "${avg_arr[@]}" + printf "Expected IPI latency(ns): %s\n" "${latency_arr[$state]}" >>"$LOG" + printf "Observed Avg IPI latency(ns) - State %s: %s\n" "${state_name_arr[$state]}" "$avg" | tee -a "$LOG" + cpuidle_disable_state $state + done +} + +# Extract the residency in microseconds and convert to nanoseconds. +# Add 200 ns so that the timer stays for a little longer than the residency +extract_residency() { + for ((state = 0; state < NUM_STATES; state++)); do + residency=$(($(cat /sys/devices/system/cpu/cpu"$IPI_SRC_CPU"/cpuidle/state"$state"/residency) * 1000 + 200)) + residency_arr+=("$residency") + done +} + +# Run the Timeout test +# $1 run for baseline - busy cpu or regular environment +# $2 destination cpu +# $3 timeout +timeout_test_once() { + dest_cpu=$2 + if [ "$1" = "baseline" ]; then + # Keep the CPU busy + taskset -c "$dest_cpu" cat /dev/random >/dev/null & + task_pid=$! + # Wait for the workload to achieve 100% CPU usage + sleep 1 + fi + taskset -c "$dest_cpu" sleep 1 + taskset -c "$dest_cpu" echo "$3" >/sys/kernel/debug/powerpc/latency_test/timeout_expected_ns + # Wait for the result to populate + sleep 0.1 + timeout_diff=$(cat /sys/kernel/debug/powerpc/latency_test/timeout_diff_ns) + src_cpu=$(cat /sys/kernel/debug/powerpc/latency_test/timeout_cpu_src) + if [ "$1" = "baseline" ]; then + kill "$task_pid" + wait "$task_pid" 2>/dev/null + fi +} + +run_timeout_tests() { + extract_residency + # Disable idle states for all CPUs + op_cpuidle "$DISABLE" + + declare -a avg_arr + printf "\n...Timeout Latency Test...\n" | tee -a "$LOG" + + printf "...Baseline Timeout Latency measurement: CPU Busy...\n" >>"$LOG" + printf "%s %10s\n" "Wakeup_src" "Baseline_delay(ns)" >>"$LOG" + for cpu in "${core_arr[@]}"; do + cpu_is_online "$cpu" + local cpu_status=$? + if [ "$cpu_status" == 0 ]; then + continue + fi + timeout_test_once "baseline" "$cpu" "$TIMEOUT" + printf "%-3s %13s\n" "$src_cpu" "$timeout_diff" >>"$LOG" + avg_arr+=("$timeout_diff") + done + compute_average "${avg_arr[@]}" + printf "Baseline Avg timeout diff(ns): %s\n" "$avg" | tee -a "$LOG" + + for ((state = 0; state < NUM_STATES; state++)); do + unset avg_arr + printf "...Enabling state: %s...\n" "${state_name_arr["$state"]}" >>"$LOG" + cpuidle_enable_state "$state" + printf "%s %10s\n" "Wakeup_src" "Delay(ns)" >>"$LOG" + for cpu in "${core_arr[@]}"; do + cpu_is_online "$cpu" + local cpu_status=$? + if [ "$cpu_status" == 0 ]; then + continue + fi + timeout_test_once "test" "$cpu" "$TIMEOUT" + printf "%-3s %13s\n" "$src_cpu" "$timeout_diff" >>"$LOG" + avg_arr+=("$timeout_diff") + done + compute_average "${avg_arr[@]}" + printf "Expected timeout(ns): %s\n" "${residency_arr["$state"]}" >>"$LOG" + printf "Observed Avg timeout diff(ns) - State %s: %s\n" "${state_name_arr["$state"]}" "$avg" | tee -a "$LOG" + cpuidle_disable_state "$state" + done +} + +# Function to exit the test if not intended +exit_test() { + printf "Exiting the test. Test not intended to run.\n" + exit "$ksft_skip" +} + +printf "Running this test enables all CPU idle states by the time it concludes.\n" +printf "Note: This test does not restore previous idle state.\n" + +declare -a residency_arr +declare -a latency_arr +declare -a core_arr +declare -a first_core_arr +declare -a state_name_arr + +parse_arguments "$@" + +rm -f "$LOG" +touch "$LOG" + +NUM_CPUS=$(nproc --all) +NUM_STATES=$(ls -1 /sys/devices/system/cpu/cpu"$IPI_SRC_CPU"/cpuidle/ | wc -l) + +extract_core_information +extract_state_information + +ins_mod "$MODULE" + +run_ipi_tests +if [ "$RUN_TIMER_TEST" == "1" ]; then + run_timeout_tests +fi + +# Enable all idle states for all CPUs +op_cpuidle $ENABLE +printf "Removing %s module\n" "$MODULE" +printf "Full Output logged at: %s\n" "$LOG" + +if [ -f "$MODULE" ]; then + rmmod "$MODULE" +fi + +exit "$exit_status" diff --git a/tools/testing/selftests/powerpc/cpuidle_latency/settings b/tools/testing/selftests/powerpc/cpuidle_latency/settings new file mode 100644 index 000000000000..e7b9417537fb --- /dev/null +++ b/tools/testing/selftests/powerpc/cpuidle_latency/settings @@ -0,0 +1 @@ +timeout=0