From 08aa0d1f376e9b966568316bd2019b3c1274d885 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 21 Nov 2011 14:42:47 +0100 Subject: perf tools: Add x86 RDPMC, RDTSC test Implement a simple test for the self-monitoring data from the perf mmap data area control page: 6: x86 rdpmc test: 0: 6053 1: 60053 2: 600059 3: 6000059 4: 60000075 5: 600000247 Ok The counts are expected to increase monotonically - these are recovered via RDPMC, without calling into the kernel. It might be nice to add logic to automagically turn these numbers into OK/FAIL. Signed-off-by: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Stephane Eranian Cc: Arun Sharma Link: http://lkml.kernel.org/n/tip-evf5yii88ljdgmaihccbxxw1@git.kernel.org [ various small improvements ] Signed-off-by: Ingo Molnar diff --git a/tools/perf/builtin-test.c b/tools/perf/builtin-test.c index 2b9a7f4..439b5ed 100644 --- a/tools/perf/builtin-test.c +++ b/tools/perf/builtin-test.c @@ -15,6 +15,8 @@ #include "util/thread_map.h" #include "../../include/linux/hw_breakpoint.h" +#include + static int vmlinux_matches_kallsyms_filter(struct map *map __used, struct symbol *sym) { bool *visited = symbol__priv(sym); @@ -1296,6 +1298,173 @@ out: return (err < 0 || errs > 0) ? -1 : 0; } + +#if defined(__x86_64__) || defined(__i386__) + +#define barrier() asm volatile("" ::: "memory") + +static u64 rdpmc(unsigned int counter) +{ + unsigned int low, high; + + asm volatile("rdpmc" : "=a" (low), "=d" (high) : "c" (counter)); + + return low | ((u64)high) << 32; +} + +static u64 rdtsc(void) +{ + unsigned int low, high; + + asm volatile("rdtsc" : "=a" (low), "=d" (high)); + + return low | ((u64)high) << 32; +} + +static u64 mmap_read_self(void *addr) +{ + struct perf_event_mmap_page *pc = addr; + u32 seq, idx, time_mult = 0, time_shift = 0; + u64 count, cyc = 0, time_offset = 0, enabled, running, delta; + + do { + seq = pc->lock; + barrier(); + + enabled = pc->time_enabled; + running = pc->time_running; + + if (enabled != running) { + cyc = rdtsc(); + time_mult = pc->time_mult; + time_shift = pc->time_shift; + time_offset = pc->time_offset; + } + + idx = pc->index; + count = pc->offset; + if (idx) + count += rdpmc(idx - 1); + + barrier(); + } while (pc->lock != seq); + + if (enabled != running) { + u64 quot, rem; + + quot = (cyc >> time_shift); + rem = cyc & ((1 << time_shift) - 1); + delta = time_offset + quot * time_mult + + ((rem * time_mult) >> time_shift); + + enabled += delta; + if (idx) + running += delta; + + quot = count / running; + rem = count % running; + count = quot * enabled + (rem * enabled) / running; + } + + return count; +} + +/* + * If the RDPMC instruction faults then signal this back to the test parent task: + */ +static void segfault_handler(int sig __used, siginfo_t *info __used, void *uc __used) +{ + exit(-1); +} + +static int __test__rdpmc(void) +{ + long page_size = sysconf(_SC_PAGE_SIZE); + volatile int tmp = 0; + u64 i, loops = 1000; + int n; + int fd; + void *addr; + struct perf_event_attr attr = { + .type = PERF_TYPE_HARDWARE, + .config = PERF_COUNT_HW_INSTRUCTIONS, + .exclude_kernel = 1, + }; + u64 delta_sum = 0; + struct sigaction sa; + + sigfillset(&sa.sa_mask); + sa.sa_sigaction = segfault_handler; + sigaction(SIGSEGV, &sa, NULL); + + fprintf(stderr, "\n\n"); + + fd = sys_perf_event_open(&attr, 0, -1, -1, 0); + if (fd < 0) { + die("Error: sys_perf_event_open() syscall returned " + "with %d (%s)\n", fd, strerror(errno)); + } + + addr = mmap(NULL, page_size, PROT_READ, MAP_SHARED, fd, 0); + if (addr == (void *)(-1)) { + die("Error: mmap() syscall returned " + "with (%s)\n", strerror(errno)); + } + + for (n = 0; n < 6; n++) { + u64 stamp, now, delta; + + stamp = mmap_read_self(addr); + + for (i = 0; i < loops; i++) + tmp++; + + now = mmap_read_self(addr); + loops *= 10; + + delta = now - stamp; + fprintf(stderr, "%14d: %14Lu\n", n, (long long)delta); + + delta_sum += delta; + } + + munmap(addr, page_size); + close(fd); + + fprintf(stderr, " "); + + if (!delta_sum) + return -1; + + return 0; +} + +static int test__rdpmc(void) +{ + int status = 0; + int wret = 0; + int ret; + int pid; + + pid = fork(); + if (pid < 0) + return -1; + + if (!pid) { + ret = __test__rdpmc(); + + exit(ret); + } + + wret = waitpid(pid, &status, 0); + if (wret < 0 || status) + return -1; + + return 0; +} + +#endif + static struct test { const char *desc; int (*func)(void); @@ -1320,6 +1489,12 @@ static struct test { .desc = "parse events tests", .func = test__parse_events, }, +#if defined(__x86_64__) || defined(__i386__) + { + .desc = "x86 rdpmc test", + .func = test__rdpmc, + }, +#endif { .desc = "Validate PERF_RECORD_* events & perf_sample fields", .func = test__PERF_RECORD, @@ -1412,7 +1587,5 @@ int cmd_test(int argc, const char **argv, const char *prefix __used) if (symbol__init() < 0) return -1; - setup_pager(); - return __cmd_test(argc, argv); } -- cgit v0.10.2