perf tools: Add x86 RDPMC, RDTSC test
authorPeter Zijlstra <a.p.zijlstra@chello.nl>
Mon, 21 Nov 2011 13:42:47 +0000 (14:42 +0100)
committerIngo Molnar <mingo@elte.hu>
Wed, 21 Dec 2011 11:21:42 +0000 (12:21 +0100)
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 <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Arun Sharma <asharma@fb.com>
Link: http://lkml.kernel.org/n/tip-evf5yii88ljdgmaihccbxxw1@git.kernel.org
[ various small improvements ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
tools/perf/builtin-test.c

index 2b9a7f497a20b77015225127eb3e5df698e5b8b1..439b5ed03e643c95f9431617983dd4a369588bf5 100644 (file)
@@ -15,6 +15,8 @@
 #include "util/thread_map.h"
 #include "../../include/linux/hw_breakpoint.h"
 
 #include "util/thread_map.h"
 #include "../../include/linux/hw_breakpoint.h"
 
+#include <sys/mman.h>
+
 static int vmlinux_matches_kallsyms_filter(struct map *map __used, struct symbol *sym)
 {
        bool *visited = symbol__priv(sym);
 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;
 }
 
        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);
 static struct test {
        const char *desc;
        int (*func)(void);
@@ -1320,6 +1489,12 @@ static struct test {
                .desc = "parse events tests",
                .func = test__parse_events,
        },
                .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,
        {
                .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;
 
        if (symbol__init() < 0)
                return -1;
 
-       setup_pager();
-
        return __cmd_test(argc, argv);
 }
        return __cmd_test(argc, argv);
 }