hi, the perf test patch below is not to be merged. It's just to show how to hit issue fixed by patch 1/1.
thanks, jirka Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Corey Ashford <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Peter Zijlstra <[email protected]> Signed-off-by: Jiri Olsa <[email protected]> --- tools/perf/Makefile.perf | 1 + tools/perf/tests/builtin-test.c | 4 + tools/perf/tests/group-read-bug.c | 169 ++++++++++++++++++++++++++++++++++++++ tools/perf/tests/tests.h | 1 + 4 files changed, 175 insertions(+) create mode 100644 tools/perf/tests/group-read-bug.c diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf index 9670a16..909084f 100644 --- a/tools/perf/Makefile.perf +++ b/tools/perf/Makefile.perf @@ -419,6 +419,7 @@ endif endif LIB_OBJS += $(OUTPUT)tests/mmap-thread-lookup.o LIB_OBJS += $(OUTPUT)tests/thread-mg-share.o +LIB_OBJS += $(OUTPUT)tests/group-read-bug.o BUILTIN_OBJS += $(OUTPUT)builtin-annotate.o BUILTIN_OBJS += $(OUTPUT)builtin-bench.o diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c index 6f8b01b..2b2d544 100644 --- a/tools/perf/tests/builtin-test.c +++ b/tools/perf/tests/builtin-test.c @@ -154,6 +154,10 @@ static struct test { .func = test__hists_cumulate, }, { + .desc = "Test group read bug", + .func = test__group_read_bug, + }, + { .func = NULL, }, }; diff --git a/tools/perf/tests/group-read-bug.c b/tools/perf/tests/group-read-bug.c new file mode 100644 index 0000000..d69fabf --- /dev/null +++ b/tools/perf/tests/group-read-bug.c @@ -0,0 +1,169 @@ +#include <unistd.h> +#include <sys/syscall.h> /* For SYS_xxx definitions */ +#include <linux/perf_event.h> +#include <linux/hw_breakpoint.h> +#include <string.h> +#include <unistd.h> +#include <sys/mman.h> +#include <signal.h> +#include <pthread.h> +#include "tests.h" +#include "perf.h" +#include "debug.h" +#include "trace-event.h" + +static int fd_leader; +static bool done; +static int pid; + +static int create_event(int group_fd) +{ + struct perf_event_attr pe; + struct event_format* format; + int fd; + + memset(&pe, 0, sizeof(struct perf_event_attr)); + pe.type = PERF_TYPE_TRACEPOINT; + pe.size = sizeof(struct perf_event_attr); + + format = trace_event__tp_format("syscalls", "sys_enter_read"); + if (!format) + return TEST_FAIL; + + pe.config = format->id; + pe.sample_period = 1; + pe.sample_type = PERF_SAMPLE_ID|PERF_SAMPLE_READ; + pe.read_format = PERF_FORMAT_ID|PERF_FORMAT_GROUP; + + if (group_fd == -1) + pe.disabled = 1; + + fd = sys_perf_event_open(&pe, pid, -1, group_fd, 0); + if (fd < 0) { + pr_debug("failed opening event %llx, errno %d\n", + pe.config, errno); + return TEST_FAIL; + } + + return fd; +} + +static __u64 read_head(struct perf_event_mmap_page *pc) +{ + __u64 head = ACCESS_ONCE(pc->data_head); + rmb(); + return head; +} + +static void write_tail(struct perf_event_mmap_page *pc, __u64 tail) +{ + mb(); + pc->data_tail = tail; +} + +static void mmap_read(struct perf_event_mmap_page *pc, int mask) +{ + __u64 old = 0; + __u64 empty = 0; + + while (!done) { + __u64 size, head; + + head = read_head(pc); + + if (old == head) { + empty++; + continue; + } + + size = head - old; + + pr_debug("empty %llu, head = %llu, size %llu\n", empty, head, size); + empty = 0; + + if ((old & mask) + size != (head & mask)) { + size = mask + 1 - (old & mask); + old += size; + } + + size = head - old; + old += size; + write_tail(pc, old); + } +} + +static void *worker_thread(void *data __maybe_unused) +{ +#define CNT 1000 + int fds[CNT]; + + while (!done) { + int i; + + for (i = 0; i < CNT; i++) + fds[i] = create_event(fd_leader); + + for (i = 0; i < CNT; i++) + close(fds[i]); + } + + return NULL; +} + +static void *gen_thread(void *data __maybe_unused) +{ + pid = syscall(SYS_gettid); + + while (!done) { + int i; + + i = read(300, &i, sizeof(i)); + } + + return NULL; +} + +static void signal_fn(int signo __maybe_unused) +{ + done = 1; +} + +int test__group_read_bug(void) +{ + pthread_t pthread, pthread_gen; + int mmap_len = page_size + (page_size << 5); + int mmap_mask = mmap_len - page_size - 1; + void *buf; + int err; + + signal(SIGINT, signal_fn); + + err = pthread_create(&pthread, NULL, gen_thread, NULL); + TEST_ASSERT_VAL("create gen", !err); + + while(!pid) { + pr_debug("waiting for pid\n"); + sleep(1); + } + + fd_leader = create_event(-1); + TEST_ASSERT_VAL("create a leader", fd_leader >= 0); + + buf = mmap(NULL, mmap_len, PROT_READ|PROT_WRITE, MAP_SHARED, fd_leader, 0); + TEST_ASSERT_VAL("mmap leader", buf != MAP_FAILED); + + err = ioctl(fd_leader, PERF_EVENT_IOC_ENABLE, 0); + TEST_ASSERT_VAL("enable leader", !err); + + err = pthread_create(&pthread_gen, NULL, worker_thread, NULL); + TEST_ASSERT_VAL("create worker", !err); + + mmap_read(buf, mmap_mask); + + munmap(buf, mmap_len); + close(fd_leader); + + pthread_join(pthread, NULL); + pthread_join(pthread_gen, NULL); + return 0; +} diff --git a/tools/perf/tests/tests.h b/tools/perf/tests/tests.h index ed64790..af43c47 100644 --- a/tools/perf/tests/tests.h +++ b/tools/perf/tests/tests.h @@ -48,6 +48,7 @@ int test__mmap_thread_lookup(void); int test__thread_mg_share(void); int test__hists_output(void); int test__hists_cumulate(void); +int test__group_read_bug(void); #if defined(__x86_64__) || defined(__i386__) || defined(__arm__) #ifdef HAVE_DWARF_UNWIND_SUPPORT -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
