From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yb1-xb34.google.com (mail-yb1-xb34.google.com [IPv6:2607:f8b0:4864:20::b34]) by sourceware.org (Postfix) with ESMTPS id 76A8B3857363 for ; Tue, 28 Jun 2022 17:14:54 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 76A8B3857363 Received: by mail-yb1-xb34.google.com with SMTP id d5so23343579yba.5 for ; Tue, 28 Jun 2022 10:14:54 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=N7aT9SjBrEptqvASuAIlh+zq4FwEwK6Dmu3l142v8Es=; b=Cue8NJDI53+HgnAyf94Tya9zxwuart0VYMcc+6zo7PSAYI/mnWE/gajdmBBP+9fruP I9TROS+8oVbMNmUxuggOOtzq4pVNQX/lPqgri4YpDgAJ2+wmhyQyoZ1oH2XDrkfPzJts fvV0u2nHZnIxI0vmsjhHc2/L1+6pQzf3H+rPEohcNs39DM/8uDXSnCFzaDvQHSD97Lfg tN2HaAG4ZsXPp2SRp/Udec2muZYTs8quFEyYPKpNuknR2RWcmuS8Zb/O3nFKWvtZF5LT 9Xzwa0oI8EH/z6+OeweDJll68T3VBsBqpiFu041VnHyUsN13+eyO0ajJfYMfvtIkuUqv /6sg== X-Gm-Message-State: AJIora/8Oq6Pa0pt20U4d0aCcNVtIDLDJJ7likm62b7SinHHlrwycoK5 GinIPTAgEIhplqmdBHKVF3om9OlEmcqYzoH5cB0= X-Google-Smtp-Source: AGRyM1u3BUXfa6CgmFeJTp5m+3k29bHnUgFlk6hCCvgAx7ZTDQDXvmqYtcZnFPrzF/TKGC+QQGR6w0lRHZ3GcWEnhGQ= X-Received: by 2002:a25:b806:0:b0:663:d35d:8b8a with SMTP id v6-20020a25b806000000b00663d35d8b8amr20802855ybj.69.1656436493810; Tue, 28 Jun 2022 10:14:53 -0700 (PDT) MIME-Version: 1.0 References: <20220518191424.3630729-1-adhemerval.zanella@linaro.org> <20220518191424.3630729-4-adhemerval.zanella@linaro.org> In-Reply-To: From: Noah Goldstein Date: Tue, 28 Jun 2022 10:14:43 -0700 Message-ID: Subject: Re: [PATCH v6 03/10] benchtests: Add arc4random benchtest To: Adhemerval Zanella Cc: GNU C Library Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-8.7 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 28 Jun 2022 17:14:56 -0000 On Tue, Jun 28, 2022 at 10:13 AM Noah Goldstein wrote: > > On Wed, May 18, 2022 at 12:15 PM Adhemerval Zanella via Libc-alpha > wrote: > > > > It shows both throughput (total bytes obtained in the test duration) > > and latecy for both arc4random and arc4random_buf with different > > sizes. > > > > Checked on x86_64-linux-gnu, aarch64-linux, and powerpc64le-linux-gnu. > > --- > > benchtests/Makefile | 5 +- > > benchtests/bench-arc4random.c | 224 ++++++++++++++++++++++++++++++++++ > > stdlib/arc4random.c | 14 +-- > > 3 files changed, 235 insertions(+), 8 deletions(-) > > create mode 100644 benchtests/bench-arc4random.c > > > > diff --git a/benchtests/Makefile b/benchtests/Makefile > > index de9de5cf58..76583d45a3 100644 > > --- a/benchtests/Makefile > > +++ b/benchtests/Makefile > > @@ -227,7 +227,10 @@ LOCALES := \ > > include ../gen-locales.mk > > endif > > > > -stdlib-benchset := strtod > > +stdlib-benchset := \ > > + arc4random \ > > + strtod \ > > + # stdlib-benchset > > > > stdio-common-benchset := sprintf > > > > diff --git a/benchtests/bench-arc4random.c b/benchtests/bench-arc4random.c > > new file mode 100644 > > index 0000000000..626f2ba48c > > --- /dev/null > > +++ b/benchtests/bench-arc4random.c > > @@ -0,0 +1,224 @@ > > +/* arc4random benchmarks. > > + Copyright (C) 2022 Free Software Foundation, Inc. > > + This file is part of the GNU C Library. > > + > > + The GNU C Library is free software; you can redistribute it and/or > > + modify it under the terms of the GNU Lesser General Public > > + License as published by the Free Software Foundation; either > > + version 2.1 of the License, or (at your option) any later version. > > + > > + The GNU C Library 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 > > + Lesser General Public License for more details. > > + > > + You should have received a copy of the GNU Lesser General Public > > + License along with the GNU C Library; if not, see > > + . */ > > + > > +#include "bench-timing.h" > > +#include "json-lib.h" > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > + > > +/* Prevent compiler to optimize away call. */ > > +#define DO_NOT_OPTIMIZE(__value) \ > > + ({ \ > > + __typeof (__value) __v = (__value); \ > > + asm volatile("" : : "r,m" (__v) : "memory");\ > > + }) > > This might be useful to have in the support header. > bench-hash-func.c has essentially the same code. Ah florian beat me to it. Can you update bench-hash-func.c when you put this in a header? Defined in bench-hash-func.c and used in bench-hash-func-kernel.h > > > + > > +static volatile sig_atomic_t timer_finished; > > + > > +static void timer_callback (int unused) > > +{ > > + timer_finished = 1; > > +} > > + > > +static timer_t timer; > > + > > +/* Run for approximately DURATION seconds, and it does not matter who > > + receive the signal (so not need to mask it on main thread). */ > > +static void > > +timer_start (void) > > +{ > > + timer_finished = 0; > > + timer = support_create_timer (DURATION, 0, false, timer_callback); > > +} > > +static void > > +timer_stop (void) > > +{ > > + support_delete_timer (timer); > > +} > > + > > +static const uint32_t sizes[] = { 0, 16, 32, 48, 64, 80, 96, 112, 128 }; > > + > > +static double > > +bench_throughput (void) > > +{ > > + uint64_t n = 0; > > + > > + struct timespec start, end; > > + clock_gettime (CLOCK_MONOTONIC, &start); > > + while (1) > > + { > > + DO_NOT_OPTIMIZE (arc4random ()); > > + n++; > > + > > + if (timer_finished == 1) > > + break; > > + } > > + clock_gettime (CLOCK_MONOTONIC, &end); > > + struct timespec diff = timespec_sub (end, start); > > + > > + double total = (double) n * sizeof (uint32_t); > > + double duration = (double) diff.tv_sec > > + + (double) diff.tv_nsec / TIMESPEC_HZ; > > + > > + return total / duration; > > +} > > + > > +static double > > +bench_latency (void) > > +{ > > + timing_t start, stop, cur; > > + const size_t iters = 1024; > > + > > + TIMING_NOW (start); > > + for (size_t i = 0; i < iters; i++) > > + DO_NOT_OPTIMIZE (arc4random ()); > > + TIMING_NOW (stop); > > + > > + TIMING_DIFF (cur, start, stop); > > + > > + return (double) (cur) / (double) iters; > > +} > > + > > +static double > > +bench_buf_throughput (size_t len) > > +{ > > + uint8_t buf[len]; > > + uint64_t n = 0; > > + > > + struct timespec start, end; > > + clock_gettime (CLOCK_MONOTONIC, &start); > > + while (1) > > + { > > + arc4random_buf (buf, len); > > + n++; > > + > > + if (timer_finished == 1) > > + break; > > + } > > + clock_gettime (CLOCK_MONOTONIC, &end); > > + struct timespec diff = timespec_sub (end, start); > > + > > + double total = (double) n * len; > > + double duration = (double) diff.tv_sec > > + + (double) diff.tv_nsec / TIMESPEC_HZ; > > + > > + return total / duration; > > +} > > + > > +static double > > +bench_buf_latency (size_t len) > > +{ > > + timing_t start, stop, cur; > > + const size_t iters = 1024; > > + > > + uint8_t buf[len]; > > + > > + TIMING_NOW (start); > > + for (size_t i = 0; i < iters; i++) > > + arc4random_buf (buf, len); > > + TIMING_NOW (stop); > > + > > + TIMING_DIFF (cur, start, stop); > > + > > + return (double) (cur) / (double) iters; > > +} > > + > > +static void > > +bench_singlethread (json_ctx_t *json_ctx) > > +{ > > + json_element_object_begin (json_ctx); > > + > > + json_array_begin (json_ctx, "throughput"); > > + for (int i = 0; i < array_length (sizes); i++) > > + { > > + timer_start (); > > + double r = sizes[i] == 0 > > + ? bench_throughput () : bench_buf_throughput (sizes[i]); > > + timer_stop (); > > + > > + json_element_double (json_ctx, r); > > + } > > + json_array_end (json_ctx); > > + > > + json_array_begin (json_ctx, "latency"); > > + for (int i = 0; i < array_length (sizes); i++) > > + { > > + timer_start (); > > + double r = sizes[i] == 0 > > + ? bench_latency () : bench_buf_latency (sizes[i]); > > + timer_stop (); > > + > > + json_element_double (json_ctx, r); > > + } > > + json_array_end (json_ctx); > > + > > + json_element_object_end (json_ctx); > > +} > > + > > +static void > > +run_bench (json_ctx_t *json_ctx, const char *name, > > + char *const*fnames, size_t fnameslen, > > + void (*bench)(json_ctx_t *ctx)) > > +{ > > + json_attr_object_begin (json_ctx, name); > > + json_array_begin (json_ctx, "functions"); > > + for (int i = 0; i < fnameslen; i++) > > + json_element_string (json_ctx, fnames[i]); > > + json_array_end (json_ctx); > > + > > + json_array_begin (json_ctx, "results"); > > + bench (json_ctx); > > + json_array_end (json_ctx); > > + json_attr_object_end (json_ctx); > > +} > > + > > +static int > > +do_test (void) > > +{ > > + char *fnames[array_length (sizes)]; > > + for (int i = 0; i < array_length (sizes); i++) > > + if (sizes[i] == 0) > > + fnames[i] = xasprintf ("arc4random"); > > + else > > + fnames[i] = xasprintf ("arc4random_buf(%u)", sizes[i]); > > + > > + json_ctx_t json_ctx; > > + json_init (&json_ctx, 0, stdout); > > + > > + json_document_begin (&json_ctx); > > + json_attr_string (&json_ctx, "timing_type", TIMING_TYPE); > > + > > + run_bench (&json_ctx, "single-thread", fnames, array_length (fnames), > > + bench_singlethread); > > + > > + json_document_end (&json_ctx); > > + > > + for (int i = 0; i < array_length (sizes); i++) > > + free (fnames[i]); > > + > > + return 0; > > +} > > + > > +#include > > diff --git a/stdlib/arc4random.c b/stdlib/arc4random.c > > index f6553dfd7d..74c917b9b9 100644 > > --- a/stdlib/arc4random.c > > +++ b/stdlib/arc4random.c > > @@ -25,9 +25,9 @@ > > #include > > #include > > > > -/* Besides the cipher state 'ctx', it keeps two counters: 'have' is the > > - current valid bytes not yet consumed in 'buf', while 'count' is the maximum > > - number of bytes until a reseed. > > +/* arc4random keeps two counters: 'have' is the current valid bytes not yet > > + consumed in 'buf' while 'count' is the maximum number of bytes until a > > + reseed. > > > > Both the initial seed and reseed try to obtain entropy from the kernel > > and abort the process if none could be obtained. > > @@ -81,10 +81,10 @@ arc4random_getrandom_failure (void) > > __libc_fatal ("Fatal glibc error: Cannot get entropy for arc4random\n"); > > } > > > > -/* Fork detection is done by checking if MADV_WIPEONFORK supported. If not > > - the fork callback will reset the state on the fork call. It does not > > - handle direct clone calls, nor vfork or _Fork (arc4random is not > > - async-signal-safe due the internal lock usage). */ > > +/* If the kernel supports MADV_WIPEONFORK it is used to provide fork > > + detection. Otherwise, the state is resetied with an atfork handler. The > > + latter does not handle direct clone calls, nor vfork or _Fork (arc4random > > + is not async-signal-safe due to the internal lock usage). */ > > static void > > arc4random_init (uint8_t *buf) > > { > > -- > > 2.34.1 > >