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/*
* Copyright (c) 2019 Arm Limited.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <vppinfra/mem.h>
#include <vppinfra/cache.h>
#include <vppinfra/lock.h>
#include <pthread.h>
#include <vppinfra/format.h>
#include <vppinfra/error.h>
#include <vppinfra/time.h>
#include <sched.h>
#include <stdlib.h>
#include <vppinfra/atomics.h>
static u32 all_threads_online = 0;
typedef struct
{
uword threads_per_core;
uword cpu_mask;
uword num_cores;
uword increment_per_thread;
clib_spinlock_t slock;
uword shared_count;
uword iterations;
} spinlock_test_main_t;
void *
inc_shared_counter (void *arg)
{
f64 *time = vec_new (f64, 1);
*time = 0;
spinlock_test_main_t *stm = arg;
/* Wait for all threads to be created */
while (!clib_atomic_load_acq_n (&all_threads_online));
f64 start = clib_cpu_time_now ();
for (uword i = 0; i < stm->increment_per_thread; i++)
{
clib_spinlock_lock (&stm->slock);
stm->shared_count++;
clib_spinlock_unlock (&stm->slock);
}
*time = clib_cpu_time_now () - start;
return time;
}
unsigned
test_spinlock (spinlock_test_main_t * stm, f64 * elapse_time)
{
int error;
uword num_threads = stm->num_cores * stm->threads_per_core;
pthread_t pthread[num_threads];
cpu_set_t cpuset;
unsigned cores_set = 0, cpu_id = 0;
for (unsigned cpu_mask = stm->cpu_mask; cpu_mask; cpu_mask >>= 1)
{
if (!(cpu_mask & 1))
{
cpu_id++;
continue;
}
CPU_ZERO (&cpuset);
CPU_SET (cpu_id, &cpuset);
for (uword t_num = 0; t_num < stm->threads_per_core; t_num++)
{
uword t_index = cores_set * stm->threads_per_core + t_num;
if (error = pthread_create (&pthread[t_index], NULL,
&inc_shared_counter, stm))
clib_unix_warning ("pthread_create failed with %d", error);
if (error = pthread_setaffinity_np (pthread[t_index],
sizeof (cpu_set_t), &cpuset))
clib_unix_warning ("pthread_setaffinity_np failed with %d",
error);
}
cores_set++;
cpu_id++;
}
/* Launch all threads */
clib_atomic_store_rel_n (&all_threads_online, 1);
for (uword thread_num = 0; thread_num < num_threads; thread_num++)
{
f64 *time;
if (error = pthread_join (pthread[thread_num], (void *) &time))
clib_unix_warning ("pthread_join failed with %d", error);
*elapse_time += *time;
vec_free (time);
}
fformat (stdout, "Time elapsed: %.4e cycles\n", *elapse_time);
return stm->shared_count;
}
uword
num_cores_in_cpu_mask (uword mask)
{
uword num_cores = 0;
for (uword cpu_mask = mask; cpu_mask; cpu_mask >>= 1)
num_cores += (cpu_mask & 1);
return num_cores;
}
int
test_spinlock_main (unformat_input_t * i)
{
spinlock_test_main_t _stm, *stm = &_stm;
clib_memset (stm, 0, sizeof (spinlock_test_main_t));
while (unformat_check_input (i) != UNFORMAT_END_OF_INPUT)
{
if (0 == unformat (i, "threads/core %d", &stm->threads_per_core)
&& 0 == unformat (i, "cpu_mask %x", &stm->cpu_mask)
&& 0 == unformat (i, "increment %d", &stm->increment_per_thread)
&& 0 == unformat (i, "iterations %d", &stm->iterations))
{
clib_unix_warning ("unknown input '%U'", format_unformat_error, i);
return 1;
}
}
stm->num_cores = num_cores_in_cpu_mask (stm->cpu_mask);
uword total_increment = stm->threads_per_core * stm->num_cores *
stm->increment_per_thread;
clib_spinlock_init (&stm->slock);
f64 average_time = 0;
for (uword trial = 0; trial < stm->iterations; trial++)
{
stm->shared_count = 0;
f64 elapse_time = 0;
if (test_spinlock (stm, &elapse_time) != total_increment)
{
clib_spinlock_free (&stm->slock);
fformat (stdout, "FAILED: expected count: %d, actual count: %d\n",
total_increment, stm->shared_count);
return 1;
}
fformat (stdout, "Trial %d SUCCESS: %d = %d\n",
trial, stm->shared_count, total_increment);
average_time = (average_time * trial + elapse_time) / (trial + 1);
fformat (stdout, "Average lock/unlock cycles %.4e\n", average_time);
}
clib_spinlock_free (&stm->slock);
return 0;
}
#ifdef CLIB_UNIX
/** Launches a number of threads to simultaneously increment a global
counter, and records timestamps for spinlock performance benchmarking
@param "threads/core [# threads/core]" - number of threads per core
@param "cpu_mask [cpu_mask]" - cpu hex string e.g. input ff sets cpus 0 - 7
@param "increment [# increments]" - number of increments per threads
@param "iterations [# iterations]" - number of iterations
@returns exit code
*/
int
main (int argc, char *argv[])
{
unformat_input_t i;
i32 ret;
clib_time_t time;
clib_mem_init (0, 3ULL << 30);
clib_time_init (&time);
unformat_init_command_line (&i, argv);
ret = test_spinlock_main (&i);
unformat_free (&i);
return ret;
}
#endif /* CLIB_UNIX */
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
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