From patchwork Sun Oct 4 12:11:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Pratik R. Sampat" X-Patchwork-Id: 11815639 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7272A15E6 for ; Sun, 4 Oct 2020 12:11:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4CEC82065E for ; Sun, 4 Oct 2020 12:11:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="rfgD3Eow" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726058AbgJDMLk (ORCPT ); Sun, 4 Oct 2020 08:11:40 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:47892 "EHLO mx0b-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725840AbgJDMLk (ORCPT ); Sun, 4 Oct 2020 08:11:40 -0400 Received: from pps.filterd (m0127361.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 094C2CP2171277; Sun, 4 Oct 2020 08:11:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=91X8Mu3bspRWSnwh/hQOP6HuneQ8skvGvXUm6r8fB5w=; b=rfgD3EowKuE1Q9IjcqhEvt0rGWgTQsGlt2MsW4dZQEpF+FOzmAEQGEknIw6WO8S/ik07 DZHmZHoTZwWKIjq6QdN2wLwAouwIjFZd0/rx3TEw7bbg96usyUrDkBRpIi8+CYpVVqOm dyZAODBR9dwj4SlSE92i8bmT+KibYAV/Xvs4XkCabjiwmCjER22votj5ot3HWkSEU5h1 5oRL92DqFbLcMDa9Uu9C3GcK4Sx67HIDZcPSHvbj3jdaVIuZDrYGyoNJDyS4yorXH1uf 77QRp4Ig5Pu8pMiCrSdrZSRJx5dPTsufvlVmd6aBmqIRotHDZ+hLaI2MGsud1uofDpYE Ew== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 33ydakgvav-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 04 Oct 2020 08:11:25 -0400 Received: from m0127361.ppops.net (m0127361.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 094C2F8i171772; Sun, 4 Oct 2020 08:11:24 -0400 Received: from ppma01fra.de.ibm.com (46.49.7a9f.ip4.static.sl-reverse.com [159.122.73.70]) by mx0a-001b2d01.pphosted.com with ESMTP id 33ydakgva3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 04 Oct 2020 08:11:24 -0400 Received: from pps.filterd (ppma01fra.de.ibm.com [127.0.0.1]) by ppma01fra.de.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 094C77lg030745; Sun, 4 Oct 2020 12:11:22 GMT Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by ppma01fra.de.ibm.com with ESMTP id 33xgx7rk0c-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 04 Oct 2020 12:11:22 +0000 Received: from d06av24.portsmouth.uk.ibm.com (d06av24.portsmouth.uk.ibm.com [9.149.105.60]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 094CBJqf29491516 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 4 Oct 2020 12:11:19 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6111342047; Sun, 4 Oct 2020 12:11:19 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7B4734203F; Sun, 4 Oct 2020 12:11:17 +0000 (GMT) Received: from pratiks-thinkpad.ibmuc.com (unknown [9.77.207.41]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Sun, 4 Oct 2020 12:11:17 +0000 (GMT) From: Pratik Rajesh Sampat To: rjw@rjwysocki.net, daniel.lezcano@linaro.org, srivatsa@csail.mit.edu, shuah@kernel.org, ego@linux.vnet.ibm.com, svaidy@linux.ibm.com, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, pratik.r.sampat@gmail.com, psampat@linux.ibm.com Subject: [RFC v5 1/1] selftests/cpuidle: Add support for cpuidle latency measurement Date: Sun, 4 Oct 2020 17:41:14 +0530 Message-Id: <20201004121114.19043-2-psampat@linux.ibm.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201004121114.19043-1-psampat@linux.ibm.com> References: <20201004121114.19043-1-psampat@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-10-04_09:2020-10-02,2020-10-04 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxlogscore=999 phishscore=0 priorityscore=1501 mlxscore=0 spamscore=0 malwarescore=0 clxscore=1015 suspectscore=2 lowpriorityscore=0 adultscore=0 impostorscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2010040089 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Measure cpuidle latencies on wakeup to determine and compare with the advertsied wakeup latencies for each idle state. Cpuidle wakeup latencies are determined for IPIs and can help determine any deviations from what is advertsied by the hardware. A baseline measurement for each case of IPIs is taken at 100 percent CPU usage to quantify for the kernel-userpsace overhead during execution. Signed-off-by: Pratik Rajesh Sampat --- tools/testing/selftests/Makefile | 1 + tools/testing/selftests/cpuidle/Makefile | 7 + tools/testing/selftests/cpuidle/cpuidle.c | 479 ++++++++++++++++++++++ tools/testing/selftests/cpuidle/settings | 1 + 4 files changed, 488 insertions(+) create mode 100644 tools/testing/selftests/cpuidle/Makefile create mode 100644 tools/testing/selftests/cpuidle/cpuidle.c create mode 100644 tools/testing/selftests/cpuidle/settings diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index 9018f45d631d..2bb0e87f76fd 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -8,6 +8,7 @@ TARGETS += cgroup TARGETS += clone3 TARGETS += core TARGETS += cpufreq +TARGETS += cpuidle TARGETS += cpu-hotplug TARGETS += drivers/dma-buf TARGETS += efivarfs diff --git a/tools/testing/selftests/cpuidle/Makefile b/tools/testing/selftests/cpuidle/Makefile new file mode 100644 index 000000000000..d332485e1bc5 --- /dev/null +++ b/tools/testing/selftests/cpuidle/Makefile @@ -0,0 +1,7 @@ +# SPDX-License-Identifier: GPL-2.0 +TEST_GEN_PROGS := cpuidle + +CFLAGS += -O2 +LDLIBS += -lpthread + +include ../lib.mk diff --git a/tools/testing/selftests/cpuidle/cpuidle.c b/tools/testing/selftests/cpuidle/cpuidle.c new file mode 100644 index 000000000000..b2f6a0e655b8 --- /dev/null +++ b/tools/testing/selftests/cpuidle/cpuidle.c @@ -0,0 +1,479 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Cpuidle latency measurement microbenchmark + * + * A mechanism to measure wakeup latency for IPI based interrupts. Results of + * this microbenchmark can be used to check and validate against the + * advertised latencies for each cpuidle state + * + * IPIs (using pipes) are used to wake the CPU up and measure the + * time difference + * + * Baseline measurements on 100 busy load are used to account for the + * kernel-userspace overhead + * + * Usage: + * ./cpuidle --mode --output + * + * Copyright (C) 2020 Pratik Rajesh Sampat , IBM + */ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define READ 0 +#define WRITE 1 + +static int pipe_fd[2]; +static int *cpu_list; +static int cpus; +static int idle_states; +static uint64_t *latency_list; + +static char *log_file = "cpuidle.log"; + +static int get_online_cpus(int *online_cpu_list, int total_cpus) +{ + char filename[80]; + int i, index = 0; + FILE *fptr; + + for (i = 0; i < total_cpus; i++) { + char status; + + sprintf(filename, "/sys/devices/system/cpu/cpu"); + sprintf(filename + strlen(filename), "%d%s", i, "/online"); + fptr = fopen(filename, "r"); + if (!fptr) + continue; + assert(fscanf(fptr, "%c", &status) != EOF); + if (status == '1') + online_cpu_list[index++] = i; + fclose(fptr); + } + return index; +} + +static uint64_t us_to_ns(uint64_t val) +{ + return val * 1000; +} + +static void get_latency(int cpu) +{ + char filename[80]; + uint64_t latency; + FILE *fptr; + int state; + + for (state = 0; state < idle_states; state++) { + sprintf(filename, "%s%d%s%d%s", "/sys/devices/system/cpu/cpu", + cpu, "/cpuidle/state", + state, "/latency"); + fptr = fopen(filename, "r"); + assert(fptr); + + assert(fscanf(fptr, "%ld", &latency) != EOF); + latency_list[state] = latency; + fclose(fptr); + } +} + +static int get_idle_state_count(int cpu) +{ + struct dirent *entry; + int dir_count = 0; + char filename[80]; + DIR *dirp; + + sprintf(filename, "%s%d%s", "/sys/devices/system/cpu/cpu", + cpu, "/cpuidle"); + + dirp = opendir(filename); + if (!dirp) + return -1; + while (entry = readdir(dirp)) { + if (entry->d_type == DT_DIR) { + if (strcmp(entry->d_name, ".") == 0 || + strcmp(entry->d_name, "..") == 0) + continue; + dir_count++; + } + } + closedir(dirp); + return dir_count; +} + +/* Enable or disable all idle states */ +static int state_all_idle(char *disable) +{ + char filename[80]; + FILE *fptr; + int i, j; + + for (i = 0; i < cpus; i++) { + for (j = 0; j < idle_states; j++) { + sprintf(filename, "%s%d%s%d%s", + "/sys/devices/system/cpu/cpu", cpu_list[i], + "/cpuidle/state", j, "/disable"); + fptr = fopen(filename, "w"); + assert(fptr); + fprintf(fptr, "%s", disable); + fclose(fptr); + } + } + return 0; +} + +/* Disable all idle states */ +static int cpuidle_disable_all_states(void) +{ + return state_all_idle("1"); +} + +static int cpuidle_enable_all_states(void) +{ + return state_all_idle("0"); +} + +static int state_operation(char *disable, int state) +{ + char filename[80]; + FILE *fptr; + int i; + + for (i = 0; i < cpus; i++) { + sprintf(filename, "%s%d%s%d%s", "/sys/devices/system/cpu/cpu", + cpu_list[i], "/cpuidle/state", state, "/disable"); + fptr = fopen(filename, "w"); + assert(fptr); + fprintf(fptr, "%s", disable); + fclose(fptr); + } + return 0; +} + +static int cpuidle_enable_state(int state) +{ + return state_operation("0", state); +} + +static int cpuidle_disable_state(int state) +{ + return state_operation("1", state); +} + +static uint64_t average(uint64_t *arr, int size) +{ + int i, sum = 0; + + assert(size != 0); + for (i = 0; i < size; i++) + sum += arr[i]; + return sum / size; +} + +static pthread_t start_thread_on(void *(*fn)(void *), void *arg, uint64_t cpu) +{ + pthread_attr_t attr; + cpu_set_t cpuset; + pthread_t tid; + int rc; + + CPU_ZERO(&cpuset); + CPU_SET(cpu, &cpuset); + + rc = pthread_attr_init(&attr); + if (rc) { + perror("pthread_attr_init"); + exit(1); + } + + rc = pthread_attr_setaffinity_np(&attr, sizeof(cpu_set_t), &cpuset); + if (rc) { + perror("pthread_attr_setaffinity_np"); + exit(1); + } + + rc = pthread_create(&tid, &attr, fn, arg); + if (rc) { + perror("pthread_create"); + exit(1); + } + return tid; +} + +void *util_full_cpu(void *unused) +{ + FILE *fptr; + + fptr = fopen("/dev/null", "w"); + assert(fptr); + while (1) { + fprintf(fptr, "0"); + nanosleep((const struct timespec[]){{0, 10L}}, NULL); + } + fclose(fptr); +} + +/* IPI based wakeup latencies */ +struct latency { + unsigned int src_cpu; + unsigned int dest_cpu; + struct timespec time_start; + struct timespec time_end; + uint64_t latency_ns; +} ipi_wakeup; + +static void *writer(void *unused) +{ + signed char c = 'P'; + + assert(write(pipe_fd[WRITE], &c, 1) == 1); + ipi_wakeup.src_cpu = sched_getcpu(); + + return NULL; +} + +static void *reader(void *unused) +{ + signed char c; + + assert(read(pipe_fd[READ], &c, 1) == 1); + ipi_wakeup.dest_cpu = sched_getcpu(); + + return NULL; +} + +static void ipi_test_once(int baseline, int src_cpu, int dest_cpu) +{ + pthread_t tid, tid1, baseline_tid; + + if (baseline) { + baseline_tid = start_thread_on(util_full_cpu, NULL, dest_cpu); + /* Run process for long enough to gain 100% usage*/ + sleep(2); + } + + clock_gettime(CLOCK_REALTIME, &ipi_wakeup.time_start); + + tid = start_thread_on(writer, NULL, src_cpu); + pthread_join(tid, NULL); + tid1 = start_thread_on(reader, NULL, dest_cpu); + pthread_join(tid1, NULL); + + clock_gettime(CLOCK_REALTIME, &ipi_wakeup.time_end); + ipi_wakeup.latency_ns = (ipi_wakeup.time_end.tv_sec - + ipi_wakeup.time_start.tv_sec) * 1000000000ULL + + ipi_wakeup.time_end.tv_nsec - ipi_wakeup.time_start.tv_nsec; + + if (baseline) + pthread_cancel(baseline_tid); +} + +static void ipi_test(int src_cpu) +{ + uint64_t avg_arr[cpus], avg_latency; + int cpu, state; + FILE *fptr; + + assert(cpuidle_disable_all_states() == 0); + + if (pipe(pipe_fd)) + exit(1); + + fptr = fopen(log_file, "a"); + fprintf(fptr, "----IPI TEST----\n"); + + fprintf(fptr, "----Baseline IPI Latency----\n"); + fprintf(fptr, "%s %10s %18s\n", "SRC_CPU", "DEST_CPU", + "Baseline_latency(ns)"); + /* Run the test as dummy once to stablize */ + ipi_test_once(1, src_cpu, cpu_list[0]); + for (cpu = 0; cpu < cpus; cpu++) { + ipi_test_once(1, src_cpu, cpu_list[cpu]); + fprintf(fptr, "%3d %10d %12ld\n", ipi_wakeup.src_cpu, + ipi_wakeup.dest_cpu, + ipi_wakeup.latency_ns); + avg_arr[cpu] = ipi_wakeup.latency_ns; + } + avg_latency = average(avg_arr, cpus); + fprintf(fptr, "Baseline average IPI latency(ns): %ld\n\n", avg_latency); + + for (state = 0; state < idle_states; state++) { + fprintf(fptr, "--Enabling state: %d--\n", state); + assert(cpuidle_enable_state(state) == 0); + fprintf(fptr, "%s %10s %18s\n", "SRC_CPU", "DEST_CPU", + "IPI_Latency(ns)"); + for (cpu = 0; cpu < cpus; cpu++) { + /* Allow sufficient cycles to go idle */ + sleep(1); + ipi_test_once(0, src_cpu, cpu_list[cpu]); + fprintf(fptr, "%3d %10d %18ld\n", ipi_wakeup.src_cpu, + ipi_wakeup.dest_cpu, + ipi_wakeup.latency_ns); + avg_arr[cpu] = ipi_wakeup.latency_ns; + } + fprintf(fptr, "Expected Latency(ns): %ld\n", + us_to_ns(latency_list[state])); + avg_latency = average(avg_arr, cpus); + fprintf(fptr, "Observed Average IPI latency(ns): %ld\n\n", + avg_latency); + assert(cpuidle_disable_state(state) == 0); + } + + assert(cpuidle_enable_all_states() == 0); + fclose(fptr); +} + +static struct option options[] = { + {"output", required_argument, 0, 'o'}, + {"mode", required_argument, 0, 'm'}, +}; + +static void usage(void) +{ + fprintf(stderr, "Usage: cpuidle \n\n"); + fprintf(stderr, "\t\t--mode=X\t(quick / full / )\n"); + fprintf(stderr, "\t\t--output=X\tOutput loc (def: cpuidle.log)\n\n"); +} + +void get_n_random_cpus(int *shf_list, int shf_size, int *list, int n) +{ + /* Shuffle the Online CPU list */ + int i; + int shuffle_index_list[shf_size]; + + for (i = 0; i < shf_size; i++) + shuffle_index_list[i] = i; + for (i = 0; i < shf_size; i++) { + int idx = i + rand() % (shf_size - i); + int temp = shuffle_index_list[i]; + + shuffle_index_list[i] = shuffle_index_list[idx]; + shuffle_index_list[idx] = temp; + } + + /* Pick the first n from the shf_list elements */ + for (i = 0; i < n; i++) + list[i] = shf_list[shuffle_index_list[i]]; +} + +int main(int argc, char *argv[]) +{ + int total_cpus, online_cpus, option_index = 0; + int *online_cpu_list; + signed char c; + FILE *fptr; + + if (getuid()) { + fprintf(stderr, "cpuidle latency test must run as root\n"); + exit(1); + } + + total_cpus = sysconf(_SC_NPROCESSORS_ONLN); + online_cpu_list = malloc(total_cpus * sizeof(int)); + if (!online_cpu_list) { + perror("Malloc failure"); + exit(1); + } + + online_cpus = get_online_cpus(&online_cpu_list[0], total_cpus); + if (!online_cpus) { + perror("Unable to get online CPUS"); + exit(1); + } + + /* Get one CPU for a quick test */ + cpus = 1; + cpu_list = malloc(1 * sizeof(int)); + srand(time(NULL)); + cpu_list[0] = online_cpu_list[(rand() % online_cpus) + 1]; + + while (1) { + c = getopt_long(argc, argv, "", options, &option_index); + if (c == -1) + break; + + switch (c) { + case 'o': + log_file = optarg; + break; + case 'm': + if (!strcmp(optarg, "full")) { + cpu_list = realloc(cpu_list, + online_cpus * sizeof(int)); + memcpy(cpu_list, online_cpu_list, + online_cpus * sizeof(int)); + cpus = online_cpus; + } else if (strcmp(optarg, "quick")) { + int opt_cpus; + + opt_cpus = atoi(optarg); + if (!opt_cpus) { + fprintf(stderr, "Error parsing mode\n"); + usage(); + exit(1); + } + if (opt_cpus > online_cpus) { + fprintf(stderr, "Number of CPUS > Online CPUs\n"); + usage(); + exit(1); + } + cpu_list = realloc(cpu_list, + opt_cpus * sizeof(int)); + get_n_random_cpus(online_cpu_list, online_cpus, + &cpu_list[0], opt_cpus); + cpus = opt_cpus; + } + break; + default: + usage(); + exit(1); + } + } + + idle_states = get_idle_state_count(online_cpu_list[0]); + if (idle_states == -1) { + perror("Unable to get idle states"); + exit(1); + } + + fptr = fopen(log_file, "w+"); + fprintf(fptr, "cpuidle latency selftests. IPI & Timers\n"); + fprintf(fptr, "Number of CPUS: %d\n", total_cpus); + fprintf(fptr, "Number of idle states: %d\n", idle_states); + fclose(fptr); + + latency_list = malloc(idle_states * sizeof(uint64_t)); + if (!latency_list) { + perror("Malloc failure"); + exit(1); + } + + get_latency(online_cpu_list[0]); + + ipi_test(online_cpu_list[0]); + printf("IPI test done\n"); + fflush(stdout); + + printf("Output logged at: %s\n", log_file); + + free(latency_list); + free(cpu_list); + free(online_cpu_list); + return 0; +} diff --git a/tools/testing/selftests/cpuidle/settings b/tools/testing/selftests/cpuidle/settings new file mode 100644 index 000000000000..e7b9417537fb --- /dev/null +++ b/tools/testing/selftests/cpuidle/settings @@ -0,0 +1 @@ +timeout=0