"param_test" is a parametrizable restartable sequences test. See the "--help" output for usage.

"param_test_benchmark" is the same as "param_test", but it removes testing book-keeping code to allow accurate benchmarks.

"param_test_compare_twice" is the same as "param_test", but it performs each comparison within rseq critical section twice, thus validating invariants. If any of the second comparisons fails, an error message is printed and the test aborts.

Signed-off-by: Mathieu Desnoyers mathieu.desnoyers@efficios.com CC: Shuah Khan shuahkh@osg.samsung.com CC: Russell King linux@arm.linux.org.uk CC: Catalin Marinas catalin.marinas@arm.com CC: Will Deacon will.deacon@arm.com CC: Thomas Gleixner tglx@linutronix.de CC: Paul Turner pjt@google.com CC: Andrew Hunter ahh@google.com CC: Peter Zijlstra peterz@infradead.org CC: Andy Lutomirski luto@amacapital.net CC: Andi Kleen andi@firstfloor.org CC: Dave Watson davejwatson@fb.com CC: Chris Lameter cl@linux.com CC: Ingo Molnar mingo@redhat.com CC: "H. Peter Anvin" hpa@zytor.com CC: Ben Maurer bmaurer@fb.com CC: Steven Rostedt rostedt@goodmis.org CC: "Paul E. McKenney" paulmck@linux.vnet.ibm.com CC: Josh Triplett josh@joshtriplett.org CC: Linus Torvalds torvalds@linux-foundation.org CC: Andrew Morton akpm@linux-foundation.org CC: Boqun Feng boqun.feng@gmail.com CC: linux-kselftest@vger.kernel.org CC: linux-api@vger.kernel.org --- Changes since v1: - Use only rseq, remove use of cpu_opv. --- tools/testing/selftests/rseq/param_test.c | 1260 +++++++++++++++++++++++++++++ 1 file changed, 1260 insertions(+) create mode 100644 tools/testing/selftests/rseq/param_test.c

diff --git a/tools/testing/selftests/rseq/param_test.c b/tools/testing/selftests/rseq/param_test.c new file mode 100644 index 000000000000..6a9f602a8718 --- /dev/null +++ b/tools/testing/selftests/rseq/param_test.c @@ -0,0 +1,1260 @@ +// SPDX-License-Identifier: LGPL-2.1 +#define _GNU_SOURCE +#include <assert.h> +#include <pthread.h> +#include <sched.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <syscall.h> +#include <unistd.h> +#include <poll.h> +#include <sys/types.h> +#include <signal.h> +#include <errno.h> +#include <stddef.h> + +static inline pid_t gettid(void) +{ + return syscall(__NR_gettid); +} + +#define NR_INJECT 9 +static int loop_cnt[NR_INJECT + 1]; + +static int loop_cnt_1 asm("asm_loop_cnt_1") __attribute__((used)); +static int loop_cnt_2 asm("asm_loop_cnt_2") __attribute__((used)); +static int loop_cnt_3 asm("asm_loop_cnt_3") __attribute__((used)); +static int loop_cnt_4 asm("asm_loop_cnt_4") __attribute__((used)); +static int loop_cnt_5 asm("asm_loop_cnt_5") __attribute__((used)); +static int loop_cnt_6 asm("asm_loop_cnt_6") __attribute__((used)); + +static int opt_modulo, verbose; + +static int opt_yield, opt_signal, opt_sleep, + opt_disable_rseq, opt_threads = 200, + opt_disable_mod = 0, opt_test = 's', opt_mb = 0; + +#ifndef RSEQ_SKIP_FASTPATH +static long long opt_reps = 5000; +#else +static long long opt_reps = 100; +#endif + +static __thread __attribute__((tls_model("initial-exec"))) +unsigned int signals_delivered; + +#ifndef BENCHMARK + +static __thread __attribute__((tls_model("initial-exec"), unused)) +unsigned int yield_mod_cnt, nr_abort; + +#define printf_verbose(fmt, ...) \ + do { \ + if (verbose) \ + printf(fmt, ## __VA_ARGS__); \ + } while (0) + +#if defined(__x86_64__) || defined(__i386__) + +#define INJECT_ASM_REG "eax" + +#define RSEQ_INJECT_CLOBBER \ + , INJECT_ASM_REG + +#ifdef __i386__ + +#define RSEQ_INJECT_ASM(n) \ + "mov asm_loop_cnt_" #n ", %%" INJECT_ASM_REG "\n\t" \ + "test %%" INJECT_ASM_REG ",%%" INJECT_ASM_REG "\n\t" \ + "jz 333f\n\t" \ + "222:\n\t" \ + "dec %%" INJECT_ASM_REG "\n\t" \ + "jnz 222b\n\t" \ + "333:\n\t" + +#elif defined(__x86_64__) + +#define RSEQ_INJECT_ASM(n) \ + "lea asm_loop_cnt_" #n "(%%rip), %%" INJECT_ASM_REG "\n\t" \ + "mov (%%" INJECT_ASM_REG "), %%" INJECT_ASM_REG "\n\t" \ + "test %%" INJECT_ASM_REG ",%%" INJECT_ASM_REG "\n\t" \ + "jz 333f\n\t" \ + "222:\n\t" \ + "dec %%" INJECT_ASM_REG "\n\t" \ + "jnz 222b\n\t" \ + "333:\n\t" + +#else +#error "Unsupported architecture" +#endif + +#elif defined(__ARMEL__) + +#define RSEQ_INJECT_INPUT \ + , [loop_cnt_1]"m"(loop_cnt[1]) \ + , [loop_cnt_2]"m"(loop_cnt[2]) \ + , [loop_cnt_3]"m"(loop_cnt[3]) \ + , [loop_cnt_4]"m"(loop_cnt[4]) \ + , [loop_cnt_5]"m"(loop_cnt[5]) \ + , [loop_cnt_6]"m"(loop_cnt[6]) + +#define INJECT_ASM_REG "r4" + +#define RSEQ_INJECT_CLOBBER \ + , INJECT_ASM_REG + +#define RSEQ_INJECT_ASM(n) \ + "ldr " INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t" \ + "cmp " INJECT_ASM_REG ", #0\n\t" \ + "beq 333f\n\t" \ + "222:\n\t" \ + "subs " INJECT_ASM_REG ", #1\n\t" \ + "bne 222b\n\t" \ + "333:\n\t" + +#elif __PPC__ + +#define RSEQ_INJECT_INPUT \ + , [loop_cnt_1]"m"(loop_cnt[1]) \ + , [loop_cnt_2]"m"(loop_cnt[2]) \ + , [loop_cnt_3]"m"(loop_cnt[3]) \ + , [loop_cnt_4]"m"(loop_cnt[4]) \ + , [loop_cnt_5]"m"(loop_cnt[5]) \ + , [loop_cnt_6]"m"(loop_cnt[6]) + +#define INJECT_ASM_REG "r18" + +#define RSEQ_INJECT_CLOBBER \ + , INJECT_ASM_REG + +#define RSEQ_INJECT_ASM(n) \ + "lwz %%" INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t" \ + "cmpwi %%" INJECT_ASM_REG ", 0\n\t" \ + "beq 333f\n\t" \ + "222:\n\t" \ + "subic. %%" INJECT_ASM_REG ", %%" INJECT_ASM_REG ", 1\n\t" \ + "bne 222b\n\t" \ + "333:\n\t" +#else +#error unsupported target +#endif + +#define RSEQ_INJECT_FAILED \ + nr_abort++; + +#define RSEQ_INJECT_C(n) \ +{ \ + int loc_i, loc_nr_loops = loop_cnt[n]; \ + \ + for (loc_i = 0; loc_i < loc_nr_loops; loc_i++) { \ + rseq_barrier(); \ + } \ + if (loc_nr_loops == -1 && opt_modulo) { \ + if (yield_mod_cnt == opt_modulo - 1) { \ + if (opt_sleep > 0) \ + poll(NULL, 0, opt_sleep); \ + if (opt_yield) \ + sched_yield(); \ + if (opt_signal) \ + raise(SIGUSR1); \ + yield_mod_cnt = 0; \ + } else { \ + yield_mod_cnt++; \ + } \ + } \ +} + +#else + +#define printf_verbose(fmt, ...) + +#endif /* BENCHMARK */ + +#include "rseq.h" + +struct percpu_lock_entry { + intptr_t v; +} __attribute__((aligned(128))); + +struct percpu_lock { + struct percpu_lock_entry c[CPU_SETSIZE]; +}; + +struct test_data_entry { + intptr_t count; +} __attribute__((aligned(128))); + +struct spinlock_test_data { + struct percpu_lock lock; + struct test_data_entry c[CPU_SETSIZE]; +}; + +struct spinlock_thread_test_data { + struct spinlock_test_data *data; + long long reps; + int reg; +}; + +struct inc_test_data { + struct test_data_entry c[CPU_SETSIZE]; +}; + +struct inc_thread_test_data { + struct inc_test_data *data; + long long reps; + int reg; +}; + +struct percpu_list_node { + intptr_t data; + struct percpu_list_node *next; +}; + +struct percpu_list_entry { + struct percpu_list_node *head; +} __attribute__((aligned(128))); + +struct percpu_list { + struct percpu_list_entry c[CPU_SETSIZE]; +}; + +#define BUFFER_ITEM_PER_CPU 100 + +struct percpu_buffer_node { + intptr_t data; +}; + +struct percpu_buffer_entry { + intptr_t offset; + intptr_t buflen; + struct percpu_buffer_node **array; +} __attribute__((aligned(128))); + +struct percpu_buffer { + struct percpu_buffer_entry c[CPU_SETSIZE]; +}; + +#define MEMCPY_BUFFER_ITEM_PER_CPU 100 + +struct percpu_memcpy_buffer_node { + intptr_t data1; + uint64_t data2; +}; + +struct percpu_memcpy_buffer_entry { + intptr_t offset; + intptr_t buflen; + struct percpu_memcpy_buffer_node *array; +} __attribute__((aligned(128))); + +struct percpu_memcpy_buffer { + struct percpu_memcpy_buffer_entry c[CPU_SETSIZE]; +}; + +/* A simple percpu spinlock. Grabs lock on current cpu. */ +static int rseq_this_cpu_lock(struct percpu_lock *lock) +{ + int cpu; + + for (;;) { + int ret; + + cpu = rseq_cpu_start(); + ret = rseq_cmpeqv_storev(&lock->c[cpu].v, + 0, 1, cpu); + if (rseq_likely(!ret)) + break; + /* Retry if comparison fails or rseq aborts. */ + } + /* + * Acquire semantic when taking lock after control dependency. + * Matches rseq_smp_store_release(). + */ + rseq_smp_acquire__after_ctrl_dep(); + return cpu; +} + +static void rseq_percpu_unlock(struct percpu_lock *lock, int cpu) +{ + assert(lock->c[cpu].v == 1); + /* + * Release lock, with release semantic. Matches + * rseq_smp_acquire__after_ctrl_dep(). + */ + rseq_smp_store_release(&lock->c[cpu].v, 0); +} + +void *test_percpu_spinlock_thread(void *arg) +{ + struct spinlock_thread_test_data *thread_data = arg; + struct spinlock_test_data *data = thread_data->data; + long long i, reps; + + if (!opt_disable_rseq && thread_data->reg && + rseq_register_current_thread()) + abort(); + reps = thread_data->reps; + for (i = 0; i < reps; i++) { + int cpu = rseq_cpu_start(); + + cpu = rseq_this_cpu_lock(&data->lock); + data->c[cpu].count++; + rseq_percpu_unlock(&data->lock, cpu); +#ifndef BENCHMARK + if (i != 0 && !(i % (reps / 10))) + printf_verbose("tid %d: count %lld\n", (int) gettid(), i); +#endif + } + printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n", + (int) gettid(), nr_abort, signals_delivered); + if (!opt_disable_rseq && thread_data->reg && + rseq_unregister_current_thread()) + abort(); + return NULL; +} + +/* + * A simple test which implements a sharded counter using a per-cpu + * lock. Obviously real applications might prefer to simply use a + * per-cpu increment; however, this is reasonable for a test and the + * lock can be extended to synchronize more complicated operations. + */ +void test_percpu_spinlock(void) +{ + const int num_threads = opt_threads; + int i, ret; + uint64_t sum; + pthread_t test_threads[num_threads]; + struct spinlock_test_data data; + struct spinlock_thread_test_data thread_data[num_threads]; + + memset(&data, 0, sizeof(data)); + for (i = 0; i < num_threads; i++) { + thread_data[i].reps = opt_reps; + if (opt_disable_mod <= 0 || (i % opt_disable_mod)) + thread_data[i].reg = 1; + else + thread_data[i].reg = 0; + thread_data[i].data = &data; + ret = pthread_create(&test_threads[i], NULL, + test_percpu_spinlock_thread, + &thread_data[i]); + if (ret) { + errno = ret; + perror("pthread_create"); + abort(); + } + } + + for (i = 0; i < num_threads; i++) { + ret = pthread_join(test_threads[i], NULL); + if (ret) { + errno = ret; + perror("pthread_join"); + abort(); + } + } + + sum = 0; + for (i = 0; i < CPU_SETSIZE; i++) + sum += data.c[i].count; + + assert(sum == (uint64_t)opt_reps * num_threads); +} + +void *test_percpu_inc_thread(void *arg) +{ + struct inc_thread_test_data *thread_data = arg; + struct inc_test_data *data = thread_data->data; + long long i, reps; + + if (!opt_disable_rseq && thread_data->reg && + rseq_register_current_thread()) + abort(); + reps = thread_data->reps; + for (i = 0; i < reps; i++) { + int ret; + + do { + int cpu; + + cpu = rseq_cpu_start(); + ret = rseq_addv(&data->c[cpu].count, 1, cpu); + } while (rseq_unlikely(ret)); +#ifndef BENCHMARK + if (i != 0 && !(i % (reps / 10))) + printf_verbose("tid %d: count %lld\n", (int) gettid(), i); +#endif + } + printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n", + (int) gettid(), nr_abort, signals_delivered); + if (!opt_disable_rseq && thread_data->reg && + rseq_unregister_current_thread()) + abort(); + return NULL; +} + +void test_percpu_inc(void) +{ + const int num_threads = opt_threads; + int i, ret; + uint64_t sum; + pthread_t test_threads[num_threads]; + struct inc_test_data data; + struct inc_thread_test_data thread_data[num_threads]; + + memset(&data, 0, sizeof(data)); + for (i = 0; i < num_threads; i++) { + thread_data[i].reps = opt_reps; + if (opt_disable_mod <= 0 || (i % opt_disable_mod)) + thread_data[i].reg = 1; + else + thread_data[i].reg = 0; + thread_data[i].data = &data; + ret = pthread_create(&test_threads[i], NULL, + test_percpu_inc_thread, + &thread_data[i]); + if (ret) { + errno = ret; + perror("pthread_create"); + abort(); + } + } + + for (i = 0; i < num_threads; i++) { + ret = pthread_join(test_threads[i], NULL); + if (ret) { + errno = ret; + perror("pthread_join"); + abort(); + } + } + + sum = 0; + for (i = 0; i < CPU_SETSIZE; i++) + sum += data.c[i].count; + + assert(sum == (uint64_t)opt_reps * num_threads); +} + +void this_cpu_list_push(struct percpu_list *list, + struct percpu_list_node *node, + int *_cpu) +{ + int cpu; + + for (;;) { + intptr_t *targetptr, newval, expect; + int ret; + + cpu = rseq_cpu_start(); + /* Load list->c[cpu].head with single-copy atomicity. */ + expect = (intptr_t)RSEQ_READ_ONCE(list->c[cpu].head); + newval = (intptr_t)node; + targetptr = (intptr_t *)&list->c[cpu].head; + node->next = (struct percpu_list_node *)expect; + ret = rseq_cmpeqv_storev(targetptr, expect, newval, cpu); + if (rseq_likely(!ret)) + break; + /* Retry if comparison fails or rseq aborts. */ + } + if (_cpu) + *_cpu = cpu; +} + +/* + * Unlike a traditional lock-less linked list; the availability of a + * rseq primitive allows us to implement pop without concerns over + * ABA-type races. + */ +struct percpu_list_node *this_cpu_list_pop(struct percpu_list *list, + int *_cpu) +{ + struct percpu_list_node *node = NULL; + int cpu; + + for (;;) { + struct percpu_list_node *head; + intptr_t *targetptr, expectnot, *load; + off_t offset; + int ret; + + cpu = rseq_cpu_start(); + targetptr = (intptr_t *)&list->c[cpu].head; + expectnot = (intptr_t)NULL; + offset = offsetof(struct percpu_list_node, next); + load = (intptr_t *)&head; + ret = rseq_cmpnev_storeoffp_load(targetptr, expectnot, + offset, load, cpu); + if (rseq_likely(!ret)) { + node = head; + break; + } + if (ret > 0) + break; + /* Retry if rseq aborts. */ + } + if (_cpu) + *_cpu = cpu; + return node; +} + +/* + * __percpu_list_pop is not safe against concurrent accesses. Should + * only be used on lists that are not concurrently modified. + */ +struct percpu_list_node *__percpu_list_pop(struct percpu_list *list, int cpu) +{ + struct percpu_list_node *node; + + node = list->c[cpu].head; + if (!node) + return NULL; + list->c[cpu].head = node->next; + return node; +} + +void *test_percpu_list_thread(void *arg) +{ + long long i, reps; + struct percpu_list *list = (struct percpu_list *)arg; + + if (!opt_disable_rseq && rseq_register_current_thread()) + abort(); + + reps = opt_reps; + for (i = 0; i < reps; i++) { + struct percpu_list_node *node; + + node = this_cpu_list_pop(list, NULL); + if (opt_yield) + sched_yield(); /* encourage shuffling */ + if (node) + this_cpu_list_push(list, node, NULL); + } + + printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n", + (int) gettid(), nr_abort, signals_delivered); + if (!opt_disable_rseq && rseq_unregister_current_thread()) + abort(); + + return NULL; +} + +/* Simultaneous modification to a per-cpu linked list from many threads. */ +void test_percpu_list(void) +{ + const int num_threads = opt_threads; + int i, j, ret; + uint64_t sum = 0, expected_sum = 0; + struct percpu_list list; + pthread_t test_threads[num_threads]; + cpu_set_t allowed_cpus; + + memset(&list, 0, sizeof(list)); + + /* Generate list entries for every usable cpu. */ + sched_getaffinity(0, sizeof(allowed_cpus), &allowed_cpus); + for (i = 0; i < CPU_SETSIZE; i++) { + if (!CPU_ISSET(i, &allowed_cpus)) + continue; + for (j = 1; j <= 100; j++) { + struct percpu_list_node *node; + + expected_sum += j; + + node = malloc(sizeof(*node)); + assert(node); + node->data = j; + node->next = list.c[i].head; + list.c[i].head = node; + } + } + + for (i = 0; i < num_threads; i++) { + ret = pthread_create(&test_threads[i], NULL, + test_percpu_list_thread, &list); + if (ret) { + errno = ret; + perror("pthread_create"); + abort(); + } + } + + for (i = 0; i < num_threads; i++) { + ret = pthread_join(test_threads[i], NULL); + if (ret) { + errno = ret; + perror("pthread_join"); + abort(); + } + } + + for (i = 0; i < CPU_SETSIZE; i++) { + struct percpu_list_node *node; + + if (!CPU_ISSET(i, &allowed_cpus)) + continue; + + while ((node = __percpu_list_pop(&list, i))) { + sum += node->data; + free(node); + } + } + + /* + * All entries should now be accounted for (unless some external + * actor is interfering with our allowed affinity while this + * test is running). + */ + assert(sum == expected_sum); +} + +bool this_cpu_buffer_push(struct percpu_buffer *buffer, + struct percpu_buffer_node *node, + int *_cpu) +{ + bool result = false; + int cpu; + + for (;;) { + intptr_t *targetptr_spec, newval_spec; + intptr_t *targetptr_final, newval_final; + intptr_t offset; + int ret; + + cpu = rseq_cpu_start(); + offset = RSEQ_READ_ONCE(buffer->c[cpu].offset); + if (offset == buffer->c[cpu].buflen) + break; + newval_spec = (intptr_t)node; + targetptr_spec = (intptr_t *)&buffer->c[cpu].array[offset]; + newval_final = offset + 1; + targetptr_final = &buffer->c[cpu].offset; + if (opt_mb) + ret = rseq_cmpeqv_trystorev_storev_release( + targetptr_final, offset, targetptr_spec, + newval_spec, newval_final, cpu); + else + ret = rseq_cmpeqv_trystorev_storev(targetptr_final, + offset, targetptr_spec, newval_spec, + newval_final, cpu); + if (rseq_likely(!ret)) { + result = true; + break; + } + /* Retry if comparison fails or rseq aborts. */ + } + if (_cpu) + *_cpu = cpu; + return result; +} + +struct percpu_buffer_node *this_cpu_buffer_pop(struct percpu_buffer *buffer, + int *_cpu) +{ + struct percpu_buffer_node *head; + int cpu; + + for (;;) { + intptr_t *targetptr, newval; + intptr_t offset; + int ret; + + cpu = rseq_cpu_start(); + /* Load offset with single-copy atomicity. */ + offset = RSEQ_READ_ONCE(buffer->c[cpu].offset); + if (offset == 0) { + head = NULL; + break; + } + head = RSEQ_READ_ONCE(buffer->c[cpu].array[offset - 1]); + newval = offset - 1; + targetptr = (intptr_t *)&buffer->c[cpu].offset; + ret = rseq_cmpeqv_cmpeqv_storev(targetptr, offset, + (intptr_t *)&buffer->c[cpu].array[offset - 1], + (intptr_t)head, newval, cpu); + if (rseq_likely(!ret)) + break; + /* Retry if comparison fails or rseq aborts. */ + } + if (_cpu) + *_cpu = cpu; + return head; +} + +/* + * __percpu_buffer_pop is not safe against concurrent accesses. Should + * only be used on buffers that are not concurrently modified. + */ +struct percpu_buffer_node *__percpu_buffer_pop(struct percpu_buffer *buffer, + int cpu) +{ + struct percpu_buffer_node *head; + intptr_t offset; + + offset = buffer->c[cpu].offset; + if (offset == 0) + return NULL; + head = buffer->c[cpu].array[offset - 1]; + buffer->c[cpu].offset = offset - 1; + return head; +} + +void *test_percpu_buffer_thread(void *arg) +{ + long long i, reps; + struct percpu_buffer *buffer = (struct percpu_buffer *)arg; + + if (!opt_disable_rseq && rseq_register_current_thread()) + abort(); + + reps = opt_reps; + for (i = 0; i < reps; i++) { + struct percpu_buffer_node *node; + + node = this_cpu_buffer_pop(buffer, NULL); + if (opt_yield) + sched_yield(); /* encourage shuffling */ + if (node) { + if (!this_cpu_buffer_push(buffer, node, NULL)) { + /* Should increase buffer size. */ + abort(); + } + } + } + + printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n", + (int) gettid(), nr_abort, signals_delivered); + if (!opt_disable_rseq && rseq_unregister_current_thread()) + abort(); + + return NULL; +} + +/* Simultaneous modification to a per-cpu buffer from many threads. */ +void test_percpu_buffer(void) +{ + const int num_threads = opt_threads; + int i, j, ret; + uint64_t sum = 0, expected_sum = 0; + struct percpu_buffer buffer; + pthread_t test_threads[num_threads]; + cpu_set_t allowed_cpus; + + memset(&buffer, 0, sizeof(buffer)); + + /* Generate list entries for every usable cpu. */ + sched_getaffinity(0, sizeof(allowed_cpus), &allowed_cpus); + for (i = 0; i < CPU_SETSIZE; i++) { + if (!CPU_ISSET(i, &allowed_cpus)) + continue; + /* Worse-case is every item in same CPU. */ + buffer.c[i].array = + malloc(sizeof(*buffer.c[i].array) * CPU_SETSIZE * + BUFFER_ITEM_PER_CPU); + assert(buffer.c[i].array); + buffer.c[i].buflen = CPU_SETSIZE * BUFFER_ITEM_PER_CPU; + for (j = 1; j <= BUFFER_ITEM_PER_CPU; j++) { + struct percpu_buffer_node *node; + + expected_sum += j; + + /* + * We could theoretically put the word-sized + * "data" directly in the buffer. However, we + * want to model objects that would not fit + * within a single word, so allocate an object + * for each node. + */ + node = malloc(sizeof(*node)); + assert(node); + node->data = j; + buffer.c[i].array[j - 1] = node; + buffer.c[i].offset++; + } + } + + for (i = 0; i < num_threads; i++) { + ret = pthread_create(&test_threads[i], NULL, + test_percpu_buffer_thread, &buffer); + if (ret) { + errno = ret; + perror("pthread_create"); + abort(); + } + } + + for (i = 0; i < num_threads; i++) { + ret = pthread_join(test_threads[i], NULL); + if (ret) { + errno = ret; + perror("pthread_join"); + abort(); + } + } + + for (i = 0; i < CPU_SETSIZE; i++) { + struct percpu_buffer_node *node; + + if (!CPU_ISSET(i, &allowed_cpus)) + continue; + + while ((node = __percpu_buffer_pop(&buffer, i))) { + sum += node->data; + free(node); + } + free(buffer.c[i].array); + } + + /* + * All entries should now be accounted for (unless some external + * actor is interfering with our allowed affinity while this + * test is running). + */ + assert(sum == expected_sum); +} + +bool this_cpu_memcpy_buffer_push(struct percpu_memcpy_buffer *buffer, + struct percpu_memcpy_buffer_node item, + int *_cpu) +{ + bool result = false; + int cpu; + + for (;;) { + intptr_t *targetptr_final, newval_final, offset; + char *destptr, *srcptr; + size_t copylen; + int ret; + + cpu = rseq_cpu_start(); + /* Load offset with single-copy atomicity. */ + offset = RSEQ_READ_ONCE(buffer->c[cpu].offset); + if (offset == buffer->c[cpu].buflen) + break; + destptr = (char *)&buffer->c[cpu].array[offset]; + srcptr = (char *)&item; + /* copylen must be <= 4kB. */ + copylen = sizeof(item); + newval_final = offset + 1; + targetptr_final = &buffer->c[cpu].offset; + if (opt_mb) + ret = rseq_cmpeqv_trymemcpy_storev_release( + targetptr_final, offset, + destptr, srcptr, copylen, + newval_final, cpu); + else + ret = rseq_cmpeqv_trymemcpy_storev(targetptr_final, + offset, destptr, srcptr, copylen, + newval_final, cpu); + if (rseq_likely(!ret)) { + result = true; + break; + } + /* Retry if comparison fails or rseq aborts. */ + } + if (_cpu) + *_cpu = cpu; + return result; +} + +bool this_cpu_memcpy_buffer_pop(struct percpu_memcpy_buffer *buffer, + struct percpu_memcpy_buffer_node *item, + int *_cpu) +{ + bool result = false; + int cpu; + + for (;;) { + intptr_t *targetptr_final, newval_final, offset; + char *destptr, *srcptr; + size_t copylen; + int ret; + + cpu = rseq_cpu_start(); + /* Load offset with single-copy atomicity. */ + offset = RSEQ_READ_ONCE(buffer->c[cpu].offset); + if (offset == 0) + break; + destptr = (char *)item; + srcptr = (char *)&buffer->c[cpu].array[offset - 1]; + /* copylen must be <= 4kB. */ + copylen = sizeof(*item); + newval_final = offset - 1; + targetptr_final = &buffer->c[cpu].offset; + ret = rseq_cmpeqv_trymemcpy_storev(targetptr_final, + offset, destptr, srcptr, copylen, + newval_final, cpu); + if (rseq_likely(!ret)) { + result = true; + break; + } + /* Retry if comparison fails or rseq aborts. */ + } + if (_cpu) + *_cpu = cpu; + return result; +} + +/* + * __percpu_memcpy_buffer_pop is not safe against concurrent accesses. Should + * only be used on buffers that are not concurrently modified. + */ +bool __percpu_memcpy_buffer_pop(struct percpu_memcpy_buffer *buffer, + struct percpu_memcpy_buffer_node *item, + int cpu) +{ + intptr_t offset; + + offset = buffer->c[cpu].offset; + if (offset == 0) + return false; + memcpy(item, &buffer->c[cpu].array[offset - 1], sizeof(*item)); + buffer->c[cpu].offset = offset - 1; + return true; +} + +void *test_percpu_memcpy_buffer_thread(void *arg) +{ + long long i, reps; + struct percpu_memcpy_buffer *buffer = (struct percpu_memcpy_buffer *)arg; + + if (!opt_disable_rseq && rseq_register_current_thread()) + abort(); + + reps = opt_reps; + for (i = 0; i < reps; i++) { + struct percpu_memcpy_buffer_node item; + bool result; + + result = this_cpu_memcpy_buffer_pop(buffer, &item, NULL); + if (opt_yield) + sched_yield(); /* encourage shuffling */ + if (result) { + if (!this_cpu_memcpy_buffer_push(buffer, item, NULL)) { + /* Should increase buffer size. */ + abort(); + } + } + } + + printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n", + (int) gettid(), nr_abort, signals_delivered); + if (!opt_disable_rseq && rseq_unregister_current_thread()) + abort(); + + return NULL; +} + +/* Simultaneous modification to a per-cpu buffer from many threads. */ +void test_percpu_memcpy_buffer(void) +{ + const int num_threads = opt_threads; + int i, j, ret; + uint64_t sum = 0, expected_sum = 0; + struct percpu_memcpy_buffer buffer; + pthread_t test_threads[num_threads]; + cpu_set_t allowed_cpus; + + memset(&buffer, 0, sizeof(buffer)); + + /* Generate list entries for every usable cpu. */ + sched_getaffinity(0, sizeof(allowed_cpus), &allowed_cpus); + for (i = 0; i < CPU_SETSIZE; i++) { + if (!CPU_ISSET(i, &allowed_cpus)) + continue; + /* Worse-case is every item in same CPU. */ + buffer.c[i].array = + malloc(sizeof(*buffer.c[i].array) * CPU_SETSIZE * + MEMCPY_BUFFER_ITEM_PER_CPU); + assert(buffer.c[i].array); + buffer.c[i].buflen = CPU_SETSIZE * MEMCPY_BUFFER_ITEM_PER_CPU; + for (j = 1; j <= MEMCPY_BUFFER_ITEM_PER_CPU; j++) { + expected_sum += 2 * j + 1; + + /* + * We could theoretically put the word-sized + * "data" directly in the buffer. However, we + * want to model objects that would not fit + * within a single word, so allocate an object + * for each node. + */ + buffer.c[i].array[j - 1].data1 = j; + buffer.c[i].array[j - 1].data2 = j + 1; + buffer.c[i].offset++; + } + } + + for (i = 0; i < num_threads; i++) { + ret = pthread_create(&test_threads[i], NULL, + test_percpu_memcpy_buffer_thread, + &buffer); + if (ret) { + errno = ret; + perror("pthread_create"); + abort(); + } + } + + for (i = 0; i < num_threads; i++) { + ret = pthread_join(test_threads[i], NULL); + if (ret) { + errno = ret; + perror("pthread_join"); + abort(); + } + } + + for (i = 0; i < CPU_SETSIZE; i++) { + struct percpu_memcpy_buffer_node item; + + if (!CPU_ISSET(i, &allowed_cpus)) + continue; + + while (__percpu_memcpy_buffer_pop(&buffer, &item, i)) { + sum += item.data1; + sum += item.data2; + } + free(buffer.c[i].array); + } + + /* + * All entries should now be accounted for (unless some external + * actor is interfering with our allowed affinity while this + * test is running). + */ + assert(sum == expected_sum); +} + +static void test_signal_interrupt_handler(int signo) +{ + signals_delivered++; +} + +static int set_signal_handler(void) +{ + int ret = 0; + struct sigaction sa; + sigset_t sigset; + + ret = sigemptyset(&sigset); + if (ret < 0) { + perror("sigemptyset"); + return ret; + } + + sa.sa_handler = test_signal_interrupt_handler; + sa.sa_mask = sigset; + sa.sa_flags = 0; + ret = sigaction(SIGUSR1, &sa, NULL); + if (ret < 0) { + perror("sigaction"); + return ret; + } + + printf_verbose("Signal handler set for SIGUSR1\n"); + + return ret; +} + +static void show_usage(int argc, char **argv) +{ + printf("Usage : %s <OPTIONS>\n", + argv[0]); + printf("OPTIONS:\n"); + printf(" [-1 loops] Number of loops for delay injection 1\n"); + printf(" [-2 loops] Number of loops for delay injection 2\n"); + printf(" [-3 loops] Number of loops for delay injection 3\n"); + printf(" [-4 loops] Number of loops for delay injection 4\n"); + printf(" [-5 loops] Number of loops for delay injection 5\n"); + printf(" [-6 loops] Number of loops for delay injection 6\n"); + printf(" [-7 loops] Number of loops for delay injection 7 (-1 to enable -m)\n"); + printf(" [-8 loops] Number of loops for delay injection 8 (-1 to enable -m)\n"); + printf(" [-9 loops] Number of loops for delay injection 9 (-1 to enable -m)\n"); + printf(" [-m N] Yield/sleep/kill every modulo N (default 0: disabled) (>= 0)\n"); + printf(" [-y] Yield\n"); + printf(" [-k] Kill thread with signal\n"); + printf(" [-s S] S: =0: disabled (default), >0: sleep time (ms)\n"); + printf(" [-t N] Number of threads (default 200)\n"); + printf(" [-r N] Number of repetitions per thread (default 5000)\n"); + printf(" [-d] Disable rseq system call (no initialization)\n"); + printf(" [-D M] Disable rseq for each M threads\n"); + printf(" [-T test] Choose test: (s)pinlock, (l)ist, (b)uffer, (m)emcpy, (i)ncrement\n"); + printf(" [-M] Push into buffer and memcpy buffer with memory barriers.\n"); + printf(" [-v] Verbose output.\n"); + printf(" [-h] Show this help.\n"); + printf("\n"); +} + +int main(int argc, char **argv) +{ + int i; + + for (i = 1; i < argc; i++) { + if (argv[i][0] != '-') + continue; + switch (argv[i][1]) { + case '1': + case '2': + case '3': + case '4': + case '5': + case '6': + case '7': + case '8': + case '9': + if (argc < i + 2) { + show_usage(argc, argv); + goto error; + } + loop_cnt[argv[i][1] - '0'] = atol(argv[i + 1]); + i++; + break; + case 'm': + if (argc < i + 2) { + show_usage(argc, argv); + goto error; + } + opt_modulo = atol(argv[i + 1]); + if (opt_modulo < 0) { + show_usage(argc, argv); + goto error; + } + i++; + break; + case 's': + if (argc < i + 2) { + show_usage(argc, argv); + goto error; + } + opt_sleep = atol(argv[i + 1]); + if (opt_sleep < 0) { + show_usage(argc, argv); + goto error; + } + i++; + break; + case 'y': + opt_yield = 1; + break; + case 'k': + opt_signal = 1; + break; + case 'd': + opt_disable_rseq = 1; + break; + case 'D': + if (argc < i + 2) { + show_usage(argc, argv); + goto error; + } + opt_disable_mod = atol(argv[i + 1]); + if (opt_disable_mod < 0) { + show_usage(argc, argv); + goto error; + } + i++; + break; + case 't': + if (argc < i + 2) { + show_usage(argc, argv); + goto error; + } + opt_threads = atol(argv[i + 1]); + if (opt_threads < 0) { + show_usage(argc, argv); + goto error; + } + i++; + break; + case 'r': + if (argc < i + 2) { + show_usage(argc, argv); + goto error; + } + opt_reps = atoll(argv[i + 1]); + if (opt_reps < 0) { + show_usage(argc, argv); + goto error; + } + i++; + break; + case 'h': + show_usage(argc, argv); + goto end; + case 'T': + if (argc < i + 2) { + show_usage(argc, argv); + goto error; + } + opt_test = *argv[i + 1]; + switch (opt_test) { + case 's': + case 'l': + case 'i': + case 'b': + case 'm': + break; + default: + show_usage(argc, argv); + goto error; + } + i++; + break; + case 'v': + verbose = 1; + break; + case 'M': + opt_mb = 1; + break; + default: + show_usage(argc, argv); + goto error; + } + } + + loop_cnt_1 = loop_cnt[1]; + loop_cnt_2 = loop_cnt[2]; + loop_cnt_3 = loop_cnt[3]; + loop_cnt_4 = loop_cnt[4]; + loop_cnt_5 = loop_cnt[5]; + loop_cnt_6 = loop_cnt[6]; + + if (set_signal_handler()) + goto error; + + if (!opt_disable_rseq && rseq_register_current_thread()) + goto error; + switch (opt_test) { + case 's': + printf_verbose("spinlock\n"); + test_percpu_spinlock(); + break; + case 'l': + printf_verbose("linked list\n"); + test_percpu_list(); + break; + case 'b': + printf_verbose("buffer\n"); + test_percpu_buffer(); + break; + case 'm': + printf_verbose("memcpy buffer\n"); + test_percpu_memcpy_buffer(); + break; + case 'i': + printf_verbose("counter increment\n"); + test_percpu_inc(); + break; + } + if (!opt_disable_rseq && rseq_unregister_current_thread()) + abort(); +end: + return 0; + +error: + return -1; +}