/* Measure nanosleep timer latency * by: john stultz (john.stultz@linaro.org) * (C) Copyright Linaro 2013 * Licensed under the GPLv2 * * To build: * $ gcc nsleep-lat.c -o nsleep-lat -lrt * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include #include #include #include #include #include #include #ifdef KTEST #include "../kselftest.h" #else static inline int ksft_exit_pass(void) { exit(0); } static inline int ksft_exit_fail(void) { exit(1); } #endif #define NSEC_PER_SEC 1000000000ULL #define UNRESONABLE_LATENCY 40000000 /* 40ms in nanosecs */ #define CLOCK_REALTIME 0 #define CLOCK_MONOTONIC 1 #define CLOCK_PROCESS_CPUTIME_ID 2 #define CLOCK_THREAD_CPUTIME_ID 3 #define CLOCK_MONOTONIC_RAW 4 #define CLOCK_REALTIME_COARSE 5 #define CLOCK_MONOTONIC_COARSE 6 #define CLOCK_BOOTTIME 7 #define CLOCK_REALTIME_ALARM 8 #define CLOCK_BOOTTIME_ALARM 9 #define CLOCK_HWSPECIFIC 10 #define CLOCK_TAI 11 #define NR_CLOCKIDS 12 #define UNSUPPORTED 0xf00f char *clockstring(int clockid) { switch (clockid) { case CLOCK_REALTIME: return "CLOCK_REALTIME"; case CLOCK_MONOTONIC: return "CLOCK_MONOTONIC"; case CLOCK_PROCESS_CPUTIME_ID: return "CLOCK_PROCESS_CPUTIME_ID"; case CLOCK_THREAD_CPUTIME_ID: return "CLOCK_THREAD_CPUTIME_ID"; case CLOCK_MONOTONIC_RAW: return "CLOCK_MONOTONIC_RAW"; case CLOCK_REALTIME_COARSE: return "CLOCK_REALTIME_COARSE"; case CLOCK_MONOTONIC_COARSE: return "CLOCK_MONOTONIC_COARSE"; case CLOCK_BOOTTIME: return "CLOCK_BOOTTIME"; case CLOCK_REALTIME_ALARM: return "CLOCK_REALTIME_ALARM"; case CLOCK_BOOTTIME_ALARM: return "CLOCK_BOOTTIME_ALARM"; case CLOCK_TAI: return "CLOCK_TAI"; }; return "UNKNOWN_CLOCKID"; } struct timespec timespec_add(struct timespec ts, unsigned long long ns) { ts.tv_nsec += ns; while (ts.tv_nsec >= NSEC_PER_SEC) { ts.tv_nsec -= NSEC_PER_SEC; ts.tv_sec++; } return ts; } long long timespec_sub(struct timespec a, struct timespec b) { long long ret = NSEC_PER_SEC * b.tv_sec + b.tv_nsec; ret -= NSEC_PER_SEC * a.tv_sec + a.tv_nsec; return ret; } int nanosleep_lat_test(int clockid, long long ns) { struct timespec start, end, target; long long latency = 0; int i, count; target.tv_sec = ns/NSEC_PER_SEC; target.tv_nsec = ns%NSEC_PER_SEC; if (clock_gettime(clockid, &start)) return UNSUPPORTED; if (clock_nanosleep(clockid, 0, &target, NULL)) return UNSUPPORTED; count = 10; /* First check relative latency */ clock_gettime(clockid, &start); for (i = 0; i < count; i++) clock_nanosleep(clockid, 0, &target, NULL); clock_gettime(clockid, &end); if (((timespec_sub(start, end)/count)-ns) > UNRESONABLE_LATENCY) { printf("Large rel latency: %lld ns :", (timespec_sub(start, end)/count)-ns); return -1; } /* Next check absolute latency */ for (i = 0; i < count; i++) { clock_gettime(clockid, &start); target = timespec_add(start, ns); clock_nanosleep(clockid, TIMER_ABSTIME, &target, NULL); clock_gettime(clockid, &end); latency += timespec_sub(target, end); } if (latency/count > UNRESONABLE_LATENCY) { printf("Large abs latency: %lld ns :", latency/count); return -1; } return 0; } int main(int argc, char **argv) { long long length; int clockid, ret; for (clockid = CLOCK_REALTIME; clockid < NR_CLOCKIDS; clockid++) { /* Skip cputime clockids since nanosleep won't increment cputime */ if (clockid == CLOCK_PROCESS_CPUTIME_ID || clockid == CLOCK_THREAD_CPUTIME_ID || clockid == CLOCK_HWSPECIFIC) continue; printf("nsleep latency %-26s ", clockstring(clockid)); length = 10; while (length <= (NSEC_PER_SEC * 10)) { ret = nanosleep_lat_test(clockid, length); if (ret) break; length *= 100; } if (ret == UNSUPPORTED) { printf("[UNSUPPORTED]\n"); continue; } if (ret < 0) { printf("[FAILED]\n"); return ksft_exit_fail(); } printf("[OK]\n"); } return ksft_exit_pass(); } ner <tglx@linutronix.de>2017-01-31 23:58:38 +0100 committerIngo Molnar <mingo@kernel.org>2017-02-01 08:37:27 +0100 commitdd86e373e09fb16b83e8adf5c48c421a4ca76468 (patch) tree55703c2ea8584e303e342090614e0aab3509ab21 /fs/befs/debug.c parent0b3589be9b98994ce3d5aeca52445d1f5627c4ba (diff)
perf/x86/intel/rapl: Make package handling more robust
The package management code in RAPL relies on package mapping being available before a CPU is started. This changed with: 9d85eb9119f4 ("x86/smpboot: Make logical package management more robust") because the ACPI/BIOS information turned out to be unreliable, but that left RAPL in broken state. This was not noticed because on a regular boot all CPUs are online before RAPL is initialized. A possible fix would be to reintroduce the mess which allocates a package data structure in CPU prepare and when it turns out to already exist in starting throw it away later in the CPU online callback. But that's a horrible hack and not required at all because RAPL becomes functional for perf only in the CPU online callback. That's correct because user space is not yet informed about the CPU being onlined, so nothing caan rely on RAPL being available on that particular CPU. Move the allocation to the CPU online callback and simplify the hotplug handling. At this point the package mapping is established and correct. This also adds a missing check for available package data in the event_init() function. Reported-by: Yasuaki Ishimatsu <yasu.isimatu@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Stephane Eranian <eranian@google.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Fixes: 9d85eb9119f4 ("x86/smpboot: Make logical package management more robust") Link: http://lkml.kernel.org/r/20170131230141.212593966@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'fs/befs/debug.c')