diff options
| -rw-r--r-- | tools/perf/bench/Build | 1 | ||||
| -rw-r--r-- | tools/perf/bench/bench.h | 1 | ||||
| -rw-r--r-- | tools/perf/bench/find-bit-bench.c | 135 | ||||
| -rw-r--r-- | tools/perf/builtin-bench.c | 1 |
4 files changed, 138 insertions, 0 deletions
diff --git a/tools/perf/bench/Build b/tools/perf/bench/Build index 560eb9711ea2..dd68a40a790c 100644 --- a/tools/perf/bench/Build +++ b/tools/perf/bench/Build @@ -11,6 +11,7 @@ perf-y += epoll-wait.o perf-y += epoll-ctl.o perf-y += synthesize.o perf-y += kallsyms-parse.o +perf-y += find-bit-bench.o perf-$(CONFIG_X86_64) += mem-memcpy-x86-64-lib.o perf-$(CONFIG_X86_64) += mem-memcpy-x86-64-asm.o diff --git a/tools/perf/bench/bench.h b/tools/perf/bench/bench.h index 49bc8ed3042a..2804812d4154 100644 --- a/tools/perf/bench/bench.h +++ b/tools/perf/bench/bench.h @@ -36,6 +36,7 @@ int bench_sched_pipe(int argc, const char **argv); int bench_syscall_basic(int argc, const char **argv); int bench_mem_memcpy(int argc, const char **argv); int bench_mem_memset(int argc, const char **argv); +int bench_mem_find_bit(int argc, const char **argv); int bench_futex_hash(int argc, const char **argv); int bench_futex_wake(int argc, const char **argv); int bench_futex_wake_parallel(int argc, const char **argv); diff --git a/tools/perf/bench/find-bit-bench.c b/tools/perf/bench/find-bit-bench.c new file mode 100644 index 000000000000..fa90f3e9d368 --- /dev/null +++ b/tools/perf/bench/find-bit-bench.c @@ -0,0 +1,135 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Benchmark find_next_bit and related bit operations. + * + * Copyright 2020 Google LLC. + */ +#include <stdlib.h> +#include "bench.h" +#include "../util/stat.h" +#include <linux/bitmap.h> +#include <linux/bitops.h> +#include <linux/time64.h> +#include <subcmd/parse-options.h> + +static unsigned int outer_iterations = 5; +static unsigned int inner_iterations = 100000; + +static const struct option options[] = { + OPT_UINTEGER('i', "outer-iterations", &outer_iterations, + "Number of outerer iterations used"), + OPT_UINTEGER('j', "inner-iterations", &inner_iterations, + "Number of outerer iterations used"), + OPT_END() +}; + +static const char *const bench_usage[] = { + "perf bench mem find_bit <options>", + NULL +}; + +static unsigned int accumulator; +static unsigned int use_of_val; + +static noinline void workload(int val) +{ + use_of_val += val; + accumulator++; +} + +#if (defined(__i386__) || defined(__x86_64__)) && defined(__GCC_ASM_FLAG_OUTPUTS__) +static bool asm_test_bit(long nr, const unsigned long *addr) +{ + bool oldbit; + + asm volatile("bt %2,%1" + : "=@ccc" (oldbit) + : "m" (*(unsigned long *)addr), "Ir" (nr) : "memory"); + + return oldbit; +} +#else +#define asm_test_bit test_bit +#endif + +static int do_for_each_set_bit(unsigned int num_bits) +{ + unsigned long *to_test = bitmap_alloc(num_bits); + struct timeval start, end, diff; + u64 runtime_us; + struct stats fb_time_stats, tb_time_stats; + double time_average, time_stddev; + unsigned int bit, i, j; + unsigned int set_bits, skip; + unsigned int old; + + init_stats(&fb_time_stats); + init_stats(&tb_time_stats); + + for (set_bits = 1; set_bits <= num_bits; set_bits <<= 1) { + bitmap_zero(to_test, num_bits); + skip = num_bits / set_bits; + for (i = 0; i < num_bits; i += skip) + set_bit(i, to_test); + + for (i = 0; i < outer_iterations; i++) { + old = accumulator; + gettimeofday(&start, NULL); + for (j = 0; j < inner_iterations; j++) { + for_each_set_bit(bit, to_test, num_bits) + workload(bit); + } + gettimeofday(&end, NULL); + assert(old + (inner_iterations * set_bits) == accumulator); + timersub(&end, &start, &diff); + runtime_us = diff.tv_sec * USEC_PER_SEC + diff.tv_usec; + update_stats(&fb_time_stats, runtime_us); + + old = accumulator; + gettimeofday(&start, NULL); + for (j = 0; j < inner_iterations; j++) { + for (bit = 0; bit < num_bits; bit++) { + if (asm_test_bit(bit, to_test)) + workload(bit); + } + } + gettimeofday(&end, NULL); + assert(old + (inner_iterations * set_bits) == accumulator); + timersub(&end, &start, &diff); + runtime_us = diff.tv_sec * USEC_PER_SEC + diff.tv_usec; + update_stats(&tb_time_stats, runtime_us); + } + + printf("%d operations %d bits set of %d bits\n", + inner_iterations, set_bits, num_bits); + time_average = avg_stats(&fb_time_stats); + time_stddev = stddev_stats(&fb_time_stats); + printf(" Average for_each_set_bit took: %.3f usec (+- %.3f usec)\n", + time_average, time_stddev); + time_average = avg_stats(&tb_time_stats); + time_stddev = stddev_stats(&tb_time_stats); + printf(" Average test_bit loop took: %.3f usec (+- %.3f usec)\n", + time_average, time_stddev); + + if (use_of_val == accumulator) /* Try to avoid compiler tricks. */ + printf("\n"); + } + bitmap_free(to_test); + return 0; +} + +int bench_mem_find_bit(int argc, const char **argv) +{ + int err = 0, i; + + argc = parse_options(argc, argv, options, bench_usage, 0); + if (argc) { + usage_with_options(bench_usage, options); + exit(EXIT_FAILURE); + } + + for (i = 1; i <= 2048; i <<= 1) + do_for_each_set_bit(i); + + return err; +} diff --git a/tools/perf/builtin-bench.c b/tools/perf/builtin-bench.c index 4094cbe40ba0..4f176039fc8f 100644 --- a/tools/perf/builtin-bench.c +++ b/tools/perf/builtin-bench.c @@ -59,6 +59,7 @@ static struct bench syscall_benchmarks[] = { static struct bench mem_benchmarks[] = { { "memcpy", "Benchmark for memcpy() functions", bench_mem_memcpy }, { "memset", "Benchmark for memset() functions", bench_mem_memset }, + { "find_bit", "Benchmark for find_bit() functions", bench_mem_find_bit }, { "all", "Run all memory access benchmarks", NULL }, { NULL, NULL, NULL } }; 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