[v6,03/10] benchtests: Add arc4random benchtest
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Commit Message
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
Comments
* Adhemerval Zanella via Libc-alpha:
> 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 @@
> +/* Prevent compiler to optimize away call. */
> +#define DO_NOT_OPTIMIZE(__value) \
> + ({ \
> + __typeof (__value) __v = (__value); \
> + asm volatile("" : : "r,m" (__v) : "memory");\
> + })
Missing space after “volatile”.
Maybe this should be a generic building block for benchtests?
> +static void
> +run_bench (json_ctx_t *json_ctx, const char *name,
> + char *const*fnames, size_t fnameslen,
> + void (*bench)(json_ctx_t *ctx))
Missing space between “)(”.
> 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 <sys/param.h>
> #include <sys/random.h>
>
> -/* 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)
> {
I think this belongs into some other patch.
Thanks,
Florian
> On 28 Jun 2022, at 09:01, Florian Weimer <fweimer@redhat.com> wrote:
>
> * Adhemerval Zanella via Libc-alpha:
>
>> 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 @@
>
>> +/* Prevent compiler to optimize away call. */
>> +#define DO_NOT_OPTIMIZE(__value) \
>> + ({ \
>> + __typeof (__value) __v = (__value); \
>> + asm volatile("" : : "r,m" (__v) : "memory");\
>> + })
>
> Missing space after “volatile”.
Ack.
>
> Maybe this should be a generic building block for benchtests?
Indeed, I moved it to benchtests/bench-util.h.
>
>> +static void
>> +run_bench (json_ctx_t *json_ctx, const char *name,
>> + char *const*fnames, size_t fnameslen,
>> + void (*bench)(json_ctx_t *ctx))
>
> Missing space between “)(”.
Ack.
>
>
>> 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 <sys/param.h>
>> #include <sys/random.h>
>>
>> -/* 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)
>> {
>
> I think this belongs into some other patch.
Indeed, I will fix it.
>
> Thanks,
> Florian
>
On Wed, May 18, 2022 at 12:15 PM Adhemerval Zanella via Libc-alpha
<libc-alpha@sourceware.org> 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
> + <https://www.gnu.org/licenses/>. */
> +
> +#include "bench-timing.h"
> +#include "json-lib.h"
> +#include <array_length.h>
> +#include <intprops.h>
> +#include <signal.h>
> +#include <stdbool.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <support/support.h>
> +#include <support/timespec.h>
> +#include <support/xthread.h>
> +
> +/* 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.
> +
> +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 <support/test-driver.c>
> 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 <sys/param.h>
> #include <sys/random.h>
>
> -/* 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
>
On Tue, Jun 28, 2022 at 10:13 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> On Wed, May 18, 2022 at 12:15 PM Adhemerval Zanella via Libc-alpha
> <libc-alpha@sourceware.org> 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
> > + <https://www.gnu.org/licenses/>. */
> > +
> > +#include "bench-timing.h"
> > +#include "json-lib.h"
> > +#include <array_length.h>
> > +#include <intprops.h>
> > +#include <signal.h>
> > +#include <stdbool.h>
> > +#include <stdio.h>
> > +#include <stdlib.h>
> > +#include <support/support.h>
> > +#include <support/timespec.h>
> > +#include <support/xthread.h>
> > +
> > +/* 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 <support/test-driver.c>
> > 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 <sys/param.h>
> > #include <sys/random.h>
> >
> > -/* 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
> >
> On 28 Jun 2022, at 14:14, Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> On Tue, Jun 28, 2022 at 10:13 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> 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
Alright.
@@ -227,7 +227,10 @@ LOCALES := \
include ../gen-locales.mk
endif
-stdlib-benchset := strtod
+stdlib-benchset := \
+ arc4random \
+ strtod \
+ # stdlib-benchset
stdio-common-benchset := sprintf
new file mode 100644
@@ -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
+ <https://www.gnu.org/licenses/>. */
+
+#include "bench-timing.h"
+#include "json-lib.h"
+#include <array_length.h>
+#include <intprops.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <support/support.h>
+#include <support/timespec.h>
+#include <support/xthread.h>
+
+/* Prevent compiler to optimize away call. */
+#define DO_NOT_OPTIMIZE(__value) \
+ ({ \
+ __typeof (__value) __v = (__value); \
+ asm volatile("" : : "r,m" (__v) : "memory");\
+ })
+
+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 <support/test-driver.c>
@@ -25,9 +25,9 @@
#include <sys/param.h>
#include <sys/random.h>
-/* 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)
{