Hi, add an option to override auto-detection of cpu count. Defaults to auto-detection, of course.
-Thilo
From 38612f3e1339354dbaa6be4f36072320ff71c707 Mon Sep 17 00:00:00 2001 From: Thilo Borgmann <thilo.borgm...@mail.de> Date: Sat, 5 Jun 2021 14:26:23 +0200 Subject: [PATCH] fftools/cmdutils.c: Add cmd line option to override detection of cpu count Suggested-By: ffm...@fb.com --- doc/fftools-common-opts.texi | 7 +++++++ fftools/cmdutils.c | 27 +++++++++++++++++++++++++++ fftools/cmdutils.h | 7 +++++++ libavutil/cpu.c | 14 ++++++++++++++ libavutil/cpu.h | 6 ++++++ 5 files changed, 61 insertions(+) diff --git a/doc/fftools-common-opts.texi b/doc/fftools-common-opts.texi index 5260ecb8f3..7643dd8396 100644 --- a/doc/fftools-common-opts.texi +++ b/doc/fftools-common-opts.texi @@ -353,6 +353,13 @@ Possible flags for this option are: @end table @end table +@item -cpucount @var{count} (@emph{global}) +Override detection of CPU count. This option is intended +for testing. Do not use it unless you know what you're doing. +@example +ffmpeg -cpucount 2 +@end example + @item -max_alloc @var{bytes} Set the maximum size limit for allocating a block on the heap by ffmpeg's family of malloc functions. Exercise @strong{extreme caution} when using diff --git a/fftools/cmdutils.c b/fftools/cmdutils.c index 4eb68d2201..583a706e5d 100644 --- a/fftools/cmdutils.c +++ b/fftools/cmdutils.c @@ -72,6 +72,7 @@ AVDictionary *format_opts, *codec_opts, *resample_opts; static FILE *report_file; static int report_file_level = AV_LOG_DEBUG; int hide_banner = 0; +int cpu_count = -1; enum show_muxdemuxers { SHOW_DEFAULT, @@ -866,6 +867,32 @@ int opt_cpuflags(void *optctx, const char *opt, const char *arg) return 0; } +int opt_cpucount(void *optctx, const char *opt, const char *arg) +{ + int ret; + int count; + + static const AVOption opts[] = { + {"count", NULL, 0, AV_OPT_TYPE_INT, { .i64 = -1}, -1, INT_MAX, NULL}, + {NULL}, + }; + static const AVClass class = { + .class_name = "cpucount", + .item_name = av_default_item_name, + .option = opts, + .version = LIBAVUTIL_VERSION_INT, + }; + const AVClass *pclass = &class; + + ret = av_opt_eval_int(&pclass, opts, arg, &count); + + if (!ret) { + av_force_cpu_count(count); + } + + return ret; +} + int opt_loglevel(void *optctx, const char *opt, const char *arg) { const struct { const char *name; int level; } log_levels[] = { diff --git a/fftools/cmdutils.h b/fftools/cmdutils.h index 1917510589..29a45dd0be 100644 --- a/fftools/cmdutils.h +++ b/fftools/cmdutils.h @@ -50,6 +50,7 @@ extern AVDictionary *sws_dict; extern AVDictionary *swr_opts; extern AVDictionary *format_opts, *codec_opts, *resample_opts; extern int hide_banner; +extern int cpu_count; /** * Register a program-specific cleanup routine. @@ -88,6 +89,11 @@ void log_callback_help(void* ptr, int level, const char* fmt, va_list vl); */ int opt_cpuflags(void *optctx, const char *opt, const char *arg); +/** + * Override the cpucount. + */ +int opt_cpucount(void *optctx, const char *opt, const char *arg); + /** * Fallback for options that are not explicitly handled, these will be * parsed through AVOptions. @@ -239,6 +245,7 @@ void show_help_options(const OptionDef *options, const char *msg, int req_flags, { "report", 0, { .func_arg = opt_report }, "generate a report" }, \ { "max_alloc", HAS_ARG, { .func_arg = opt_max_alloc }, "set maximum size of a single allocated block", "bytes" }, \ { "cpuflags", HAS_ARG | OPT_EXPERT, { .func_arg = opt_cpuflags }, "force specific cpu flags", "flags" }, \ + { "cpucount", HAS_ARG | OPT_EXPERT, { .func_arg = opt_cpucount }, "force specific cpu count", "count" }, \ { "hide_banner", OPT_BOOL | OPT_EXPERT, {&hide_banner}, "do not show program banner", "hide_banner" }, \ CMDUTILS_COMMON_OPTIONS_AVDEVICE \ diff --git a/libavutil/cpu.c b/libavutil/cpu.c index 52f6b9a3bf..ccd5b5adac 100644 --- a/libavutil/cpu.c +++ b/libavutil/cpu.c @@ -48,6 +48,7 @@ #endif static atomic_int cpu_flags = ATOMIC_VAR_INIT(-1); +static atomic_int cpu_count = ATOMIC_VAR_INIT(-1); static int get_cpu_flags(void) { @@ -306,14 +307,27 @@ int av_cpu_count(void) nb_cpus = sysinfo.dwNumberOfProcessors; #endif + int count = atomic_load_explicit(&cpu_count, memory_order_relaxed); + if (!printed) { av_log(NULL, AV_LOG_DEBUG, "detected %d logical cores\n", nb_cpus); + if (count > 0) { + av_log(NULL, AV_LOG_DEBUG, "overriding to %d logical cores\n", count); + } printed = 1; } + if (count > 0) { + nb_cpus = count; + } + return nb_cpus; } +void av_force_cpu_count(int count){ + atomic_store_explicit(&cpu_count, count, memory_order_relaxed); +} + size_t av_cpu_max_align(void) { if (ARCH_MIPS) diff --git a/libavutil/cpu.h b/libavutil/cpu.h index 83099dd969..9c682ad50b 100644 --- a/libavutil/cpu.h +++ b/libavutil/cpu.h @@ -119,6 +119,12 @@ int av_parse_cpu_caps(unsigned *flags, const char *s); */ int av_cpu_count(void); +/** + * Overrides cpu count detection and forces the specified count. + * Count < 1 disables forcing of specific count. + */ +void av_force_cpu_count(int count); + /** * Get the maximum data alignment that may be required by FFmpeg. * -- 2.20.1 (Apple Git-117)
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