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smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aamh6zhg; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="aamh6zhg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 41A18C4CEE3; Tue, 15 Jul 2025 20:04:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752609859; bh=OKC/WrbCugWmfw4kWzTGSKbml7jMOGQBJeszqTV0fDk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aamh6zhgupF5oTFFWjy1Pl2sksJr7KEijt+a0hR2NMDnx661aHRWH4SGr+P+axPuP B378ik3uRQdDvzMWaetFgO7qu+sB9RLvS0gsucKu6pLbCLvWzGG2NKCG1Xkky5OKbz q4i1NzaljZlkuHWL4ojhfGv6hJzqRxMlxQX/2RK9p13qW9hZVQUirHMivhZFDrig8D L9xSpdj+ZskfjIzNTyjpMYUzg5Sq2A8Mlcn74At7DysSlV4vuRfXJZvb5VnOTTR4PK Nh4yGthLXjXn/mfRDg4zAK1ueXiSn+ufWwqS/jZAQQnl2ooOrlHjRwSz4xa925wmBd rbo+JCJQuf1Jg== Date: Tue, 15 Jul 2025 13:04:16 -0700 From: Namhyung Kim To: Ankur Arora Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, akpm@linux-foundation.org, david@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, mingo@redhat.com, mjguzik@gmail.com, luto@kernel.org, peterz@infradead.org, acme@kernel.org, tglx@linutronix.de, willy@infradead.org, raghavendra.kt@amd.com, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com Subject: Re: [PATCH v5 01/14] perf bench mem: Remove repetition around time measurement Message-ID: References: <20250710005926.1159009-1-ankur.a.arora@oracle.com> <20250710005926.1159009-2-ankur.a.arora@oracle.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250710005926.1159009-2-ankur.a.arora@oracle.com> Hello, On Wed, Jul 09, 2025 at 05:59:13PM -0700, Ankur Arora wrote: > We have two copies of each mem benchmark: one using cycles to > measure time, the second for gettimeofday(). > > Unify. > > Signed-off-by: Ankur Arora Reviewed-by: Namhyung Kim Thanks, Namhyung > --- > tools/perf/bench/mem-functions.c | 110 +++++++++++++------------------ > 1 file changed, 46 insertions(+), 64 deletions(-) > > diff --git a/tools/perf/bench/mem-functions.c b/tools/perf/bench/mem-functions.c > index 19d45c377ac1..8599ed96ee1f 100644 > --- a/tools/perf/bench/mem-functions.c > +++ b/tools/perf/bench/mem-functions.c > @@ -51,6 +51,11 @@ static const struct option options[] = { > OPT_END() > }; > > +union bench_clock { > + u64 cycles; > + struct timeval tv; > +}; > + > typedef void *(*memcpy_t)(void *, const void *, size_t); > typedef void *(*memset_t)(void *, int, size_t); > > @@ -91,6 +96,26 @@ static u64 get_cycles(void) > return clk; > } > > +static void clock_get(union bench_clock *t) > +{ > + if (use_cycles) > + t->cycles = get_cycles(); > + else > + BUG_ON(gettimeofday(&t->tv, NULL)); > +} > + > +static union bench_clock clock_diff(union bench_clock *s, union bench_clock *e) > +{ > + union bench_clock t; > + > + if (use_cycles) > + t.cycles = e->cycles - s->cycles; > + else > + timersub(&e->tv, &s->tv, &t.tv); > + > + return t; > +} > + > static double timeval2double(struct timeval *ts) > { > return (double)ts->tv_sec + (double)ts->tv_usec / (double)USEC_PER_SEC; > @@ -109,8 +134,7 @@ static double timeval2double(struct timeval *ts) > > struct bench_mem_info { > const struct function *functions; > - u64 (*do_cycles)(const struct function *r, size_t size, void *src, void *dst); > - double (*do_gettimeofday)(const struct function *r, size_t size, void *src, void *dst); > + union bench_clock (*do_op)(const struct function *r, size_t size, void *src, void *dst); > const char *const *usage; > bool alloc_src; > }; > @@ -119,7 +143,7 @@ static void __bench_mem_function(struct bench_mem_info *info, int r_idx, size_t > { > const struct function *r = &info->functions[r_idx]; > double result_bps = 0.0; > - u64 result_cycles = 0; > + union bench_clock rt = { 0 }; > void *src = NULL, *dst = zalloc(size); > > printf("# function '%s' (%s)\n", r->name, r->desc); > @@ -136,25 +160,23 @@ static void __bench_mem_function(struct bench_mem_info *info, int r_idx, size_t > if (bench_format == BENCH_FORMAT_DEFAULT) > printf("# Copying %s bytes ...\n\n", size_str); > > - if (use_cycles) { > - result_cycles = info->do_cycles(r, size, src, dst); > - } else { > - result_bps = info->do_gettimeofday(r, size, src, dst); > - } > + rt = info->do_op(r, size, src, dst); > > switch (bench_format) { > case BENCH_FORMAT_DEFAULT: > if (use_cycles) { > - printf(" %14lf cycles/byte\n", (double)result_cycles/size_total); > + printf(" %14lf cycles/byte\n", (double)rt.cycles/size_total); > } else { > + result_bps = size_total/timeval2double(&rt.tv); > print_bps(result_bps); > } > break; > > case BENCH_FORMAT_SIMPLE: > if (use_cycles) { > - printf("%lf\n", (double)result_cycles/size_total); > + printf("%lf\n", (double)rt.cycles/size_total); > } else { > + result_bps = size_total/timeval2double(&rt.tv); > printf("%lf\n", result_bps); > } > break; > @@ -235,38 +257,21 @@ static void memcpy_prefault(memcpy_t fn, size_t size, void *src, void *dst) > fn(dst, src, size); > } > > -static u64 do_memcpy_cycles(const struct function *r, size_t size, void *src, void *dst) > +static union bench_clock do_memcpy(const struct function *r, size_t size, > + void *src, void *dst) > { > - u64 cycle_start = 0ULL, cycle_end = 0ULL; > + union bench_clock start, end; > memcpy_t fn = r->fn.memcpy; > int i; > > memcpy_prefault(fn, size, src, dst); > > - cycle_start = get_cycles(); > + clock_get(&start); > for (i = 0; i < nr_loops; ++i) > fn(dst, src, size); > - cycle_end = get_cycles(); > + clock_get(&end); > > - return cycle_end - cycle_start; > -} > - > -static double do_memcpy_gettimeofday(const struct function *r, size_t size, void *src, void *dst) > -{ > - struct timeval tv_start, tv_end, tv_diff; > - memcpy_t fn = r->fn.memcpy; > - int i; > - > - memcpy_prefault(fn, size, src, dst); > - > - BUG_ON(gettimeofday(&tv_start, NULL)); > - for (i = 0; i < nr_loops; ++i) > - fn(dst, src, size); > - BUG_ON(gettimeofday(&tv_end, NULL)); > - > - timersub(&tv_end, &tv_start, &tv_diff); > - > - return (double)(((double)size * nr_loops) / timeval2double(&tv_diff)); > + return clock_diff(&start, &end); > } > > struct function memcpy_functions[] = { > @@ -292,8 +297,7 @@ int bench_mem_memcpy(int argc, const char **argv) > { > struct bench_mem_info info = { > .functions = memcpy_functions, > - .do_cycles = do_memcpy_cycles, > - .do_gettimeofday = do_memcpy_gettimeofday, > + .do_op = do_memcpy, > .usage = bench_mem_memcpy_usage, > .alloc_src = true, > }; > @@ -301,9 +305,10 @@ int bench_mem_memcpy(int argc, const char **argv) > return bench_mem_common(argc, argv, &info); > } > > -static u64 do_memset_cycles(const struct function *r, size_t size, void *src __maybe_unused, void *dst) > +static union bench_clock do_memset(const struct function *r, size_t size, > + void *src __maybe_unused, void *dst) > { > - u64 cycle_start = 0ULL, cycle_end = 0ULL; > + union bench_clock start, end; > memset_t fn = r->fn.memset; > int i; > > @@ -313,34 +318,12 @@ static u64 do_memset_cycles(const struct function *r, size_t size, void *src __m > */ > fn(dst, -1, size); > > - cycle_start = get_cycles(); > + clock_get(&start); > for (i = 0; i < nr_loops; ++i) > fn(dst, i, size); > - cycle_end = get_cycles(); > + clock_get(&end); > > - return cycle_end - cycle_start; > -} > - > -static double do_memset_gettimeofday(const struct function *r, size_t size, void *src __maybe_unused, void *dst) > -{ > - struct timeval tv_start, tv_end, tv_diff; > - memset_t fn = r->fn.memset; > - int i; > - > - /* > - * We prefault the freshly allocated memory range here, > - * to not measure page fault overhead: > - */ > - fn(dst, -1, size); > - > - BUG_ON(gettimeofday(&tv_start, NULL)); > - for (i = 0; i < nr_loops; ++i) > - fn(dst, i, size); > - BUG_ON(gettimeofday(&tv_end, NULL)); > - > - timersub(&tv_end, &tv_start, &tv_diff); > - > - return (double)(((double)size * nr_loops) / timeval2double(&tv_diff)); > + return clock_diff(&start, &end); > } > > static const char * const bench_mem_memset_usage[] = { > @@ -366,8 +349,7 @@ int bench_mem_memset(int argc, const char **argv) > { > struct bench_mem_info info = { > .functions = memset_functions, > - .do_cycles = do_memset_cycles, > - .do_gettimeofday = do_memset_gettimeofday, > + .do_op = do_memset, > .usage = bench_mem_memset_usage, > }; > > -- > 2.43.5 >