There can be a significant gap in memset/memcpy performance depending on the size of the region being operated on. With chunk-size=4kb: $ echo madvise > /sys/kernel/mm/transparent_hugepage/enabled $ perf bench mem memset -p 4kb -k 4kb -s 4gb -l 10 -f x86-64-stosq # Running 'mem/memset' benchmark: # function 'x86-64-stosq' (movsq-based memset() in arch/x86/lib/memset_64.S) # Copying 4gb bytes ... 13.011655 GB/sec With chunk-size=1gb: $ echo madvise > /sys/kernel/mm/transparent_hugepage/enabled $ perf bench mem memset -p 4kb -k 1gb -s 4gb -l 10 -f x86-64-stosq # Running 'mem/memset' benchmark: # function 'x86-64-stosq' (movsq-based memset() in arch/x86/lib/memset_64.S) # Copying 4gb bytes ... 21.936355 GB/sec So, allow the user to specify the chunk-size. The default value is identical to the total size of the region, which preserves current behaviour. Reviewed-by: Namhyung Kim Signed-off-by: Ankur Arora --- tools/perf/Documentation/perf-bench.txt | 10 ++++++++++ tools/perf/bench/mem-functions.c | 20 ++++++++++++++++++-- 2 files changed, 28 insertions(+), 2 deletions(-) diff --git a/tools/perf/Documentation/perf-bench.txt b/tools/perf/Documentation/perf-bench.txt index 04cdc31a0b0b..3d1455d880c3 100644 --- a/tools/perf/Documentation/perf-bench.txt +++ b/tools/perf/Documentation/perf-bench.txt @@ -187,6 +187,11 @@ Available units are B, KB, MB, GB and TB (case insensitive). Specify page-size for mapping memory buffers (default: 4KB). Available values are 4KB, 2MB, 1GB (case insensitive). +-k:: +--chunk:: +Specify the chunk-size for each invocation. (default: 0, or full-extent) +Available units are B, KB, MB, GB and TB (case insensitive). + -f:: --function:: Specify function to copy (default: default). @@ -216,6 +221,11 @@ Available units are B, KB, MB, GB and TB (case insensitive). Specify page-size for mapping memory buffers (default: 4KB). Available values are 4KB, 2MB, 1GB (case insensitive). +-k:: +--chunk:: +Specify the chunk-size for each invocation. (default: 0, or full-extent) +Available units are B, KB, MB, GB and TB (case insensitive). + -f:: --function:: Specify function to set (default: default). diff --git a/tools/perf/bench/mem-functions.c b/tools/perf/bench/mem-functions.c index 6aa1f02553ba..69968ba63d81 100644 --- a/tools/perf/bench/mem-functions.c +++ b/tools/perf/bench/mem-functions.c @@ -36,6 +36,7 @@ static const char *size_str = "1MB"; static const char *function_str = "all"; static const char *page_size_str = "4KB"; +static const char *chunk_size_str = "0"; static unsigned int nr_loops = 1; static bool use_cycles; static int cycles_fd; @@ -49,6 +50,10 @@ static const struct option options[] = { "Specify page-size for mapping memory buffers. " "Available sizes: 4KB, 2MB, 1GB (case insensitive)"), + OPT_STRING('k', "chunk", &chunk_size_str, "0", + "Specify the chunk-size for each invocation. " + "Available units: B, KB, MB, GB and TB (case insensitive)"), + OPT_STRING('f', "function", &function_str, "all", "Specify the function to run, \"all\" runs all available functions, \"help\" lists them"), @@ -69,6 +74,7 @@ union bench_clock { struct bench_params { size_t size; size_t size_total; + size_t chunk_size; unsigned int nr_loops; unsigned int page_shift; }; @@ -243,6 +249,14 @@ static int bench_mem_common(int argc, const char **argv, struct bench_mem_info * } p.size_total = p.size * p.nr_loops; + p.chunk_size = (size_t)perf_atoll((char *)chunk_size_str); + if ((s64)p.chunk_size < 0 || (s64)p.chunk_size > (s64)p.size) { + fprintf(stderr, "Invalid chunk_size:%s\n", chunk_size_str); + return 1; + } + if (!p.chunk_size) + p.chunk_size = p.size; + page_size = (unsigned int)perf_atoll((char *)page_size_str); if (page_size != (1 << PAGE_SHIFT_4KB) && page_size != (1 << PAGE_SHIFT_2MB) && @@ -300,7 +314,8 @@ static int do_memcpy(const struct function *r, struct bench_params *p, clock_get(&start); for (unsigned int i = 0; i < p->nr_loops; ++i) - fn(dst, src, p->size); + for (size_t off = 0; off < p->size; off += p->chunk_size) + fn(dst + off, src + off, min(p->chunk_size, p->size - off)); clock_get(&end); *rt = clock_diff(&start, &end); @@ -402,7 +417,8 @@ static int do_memset(const struct function *r, struct bench_params *p, clock_get(&start); for (unsigned int i = 0; i < p->nr_loops; ++i) - fn(dst, i, p->size); + for (size_t off = 0; off < p->size; off += p->chunk_size) + fn(dst + off, i, min(p->chunk_size, p->size - off)); clock_get(&end); *rt = clock_diff(&start, &end); -- 2.31.1