Commit 08aa0d1f authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar

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: default avatarPeter 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: default avatarIngo Molnar <mingo@elte.hu>
parent e3f3541c
......@@ -15,6 +15,8 @@
#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);
......@@ -1296,6 +1298,173 @@ static int test__PERF_RECORD(void)
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);
}
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