blob: 642d4e12abea2e37d92e0acea3fdcf692a64d374 [file] [log] [blame]
// 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(__s390__)
#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 "r12"
#define RSEQ_INJECT_CLOBBER \
, INJECT_ASM_REG
#define RSEQ_INJECT_ASM(n) \
"l %%" INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t" \
"ltr %%" INJECT_ASM_REG ", %%" INJECT_ASM_REG "\n\t" \
"je 333f\n\t" \
"222:\n\t" \
"ahi %%" INJECT_ASM_REG ", -1\n\t" \
"jnz 222b\n\t" \
"333:\n\t"
#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 defined(__AARCH64EL__)
#define RSEQ_INJECT_INPUT \
, [loop_cnt_1] "Qo" (loop_cnt[1]) \
, [loop_cnt_2] "Qo" (loop_cnt[2]) \
, [loop_cnt_3] "Qo" (loop_cnt[3]) \
, [loop_cnt_4] "Qo" (loop_cnt[4]) \
, [loop_cnt_5] "Qo" (loop_cnt[5]) \
, [loop_cnt_6] "Qo" (loop_cnt[6])
#define INJECT_ASM_REG RSEQ_ASM_TMP_REG32
#define RSEQ_INJECT_ASM(n) \
" ldr " INJECT_ASM_REG ", %[loop_cnt_" #n "]\n" \
" cbz " INJECT_ASM_REG ", 333f\n" \
"222:\n" \
" sub " INJECT_ASM_REG ", " INJECT_ASM_REG ", #1\n" \
" cbnz " INJECT_ASM_REG ", 222b\n" \
"333:\n"
#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"
#elif defined(__mips__)
#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 "$5"
#define RSEQ_INJECT_CLOBBER \
, INJECT_ASM_REG
#define RSEQ_INJECT_ASM(n) \
"lw " INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t" \
"beqz " INJECT_ASM_REG ", 333f\n\t" \
"222:\n\t" \
"addiu " INJECT_ASM_REG ", -1\n\t" \
"bnez " INJECT_ASM_REG ", 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;
}