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Diffstat (limited to 'src/vppinfra/test_spinlock.c')
| -rw-r--r-- | src/vppinfra/test_spinlock.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/src/vppinfra/test_spinlock.c b/src/vppinfra/test_spinlock.c new file mode 100644 index 00000000000..fd750d9851c --- /dev/null +++ b/src/vppinfra/test_spinlock.c @@ -0,0 +1,206 @@ +/* + * 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: + */ |