178 lines
3.2 KiB
C
178 lines
3.2 KiB
C
#include <unistd.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <sys/mman.h>
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#include <linux/types.h>
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#include "perf.h"
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#include "debug.h"
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#include "tests.h"
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#include "cloexec.h"
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#if defined(__x86_64__) || defined(__i386__)
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static u64 rdpmc(unsigned int counter)
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{
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unsigned int low, high;
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asm volatile("rdpmc" : "=a" (low), "=d" (high) : "c" (counter));
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return low | ((u64)high) << 32;
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}
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static u64 rdtsc(void)
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{
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unsigned int low, high;
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asm volatile("rdtsc" : "=a" (low), "=d" (high));
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return low | ((u64)high) << 32;
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}
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static u64 mmap_read_self(void *addr)
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{
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struct perf_event_mmap_page *pc = addr;
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u32 seq, idx, time_mult = 0, time_shift = 0;
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u64 count, cyc = 0, time_offset = 0, enabled, running, delta;
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do {
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seq = pc->lock;
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barrier();
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enabled = pc->time_enabled;
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running = pc->time_running;
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if (enabled != running) {
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cyc = rdtsc();
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time_mult = pc->time_mult;
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time_shift = pc->time_shift;
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time_offset = pc->time_offset;
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}
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idx = pc->index;
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count = pc->offset;
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if (idx)
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count += rdpmc(idx - 1);
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barrier();
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} while (pc->lock != seq);
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if (enabled != running) {
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u64 quot, rem;
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quot = (cyc >> time_shift);
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rem = cyc & ((1 << time_shift) - 1);
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delta = time_offset + quot * time_mult +
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((rem * time_mult) >> time_shift);
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enabled += delta;
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if (idx)
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running += delta;
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quot = count / running;
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rem = count % running;
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count = quot * enabled + (rem * enabled) / running;
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}
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return count;
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}
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/*
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* If the RDPMC instruction faults then signal this back to the test parent task:
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*/
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static void segfault_handler(int sig __maybe_unused,
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siginfo_t *info __maybe_unused,
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void *uc __maybe_unused)
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{
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exit(-1);
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}
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static int __test__rdpmc(void)
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{
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volatile int tmp = 0;
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u64 i, loops = 1000;
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int n;
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int fd;
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void *addr;
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struct perf_event_attr attr = {
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.type = PERF_TYPE_HARDWARE,
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.config = PERF_COUNT_HW_INSTRUCTIONS,
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.exclude_kernel = 1,
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};
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u64 delta_sum = 0;
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struct sigaction sa;
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char sbuf[STRERR_BUFSIZE];
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sigfillset(&sa.sa_mask);
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sa.sa_sigaction = segfault_handler;
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sigaction(SIGSEGV, &sa, NULL);
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fd = sys_perf_event_open(&attr, 0, -1, -1,
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perf_event_open_cloexec_flag());
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if (fd < 0) {
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pr_err("Error: sys_perf_event_open() syscall returned "
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"with %d (%s)\n", fd,
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strerror_r(errno, sbuf, sizeof(sbuf)));
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return -1;
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}
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addr = mmap(NULL, page_size, PROT_READ, MAP_SHARED, fd, 0);
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if (addr == (void *)(-1)) {
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pr_err("Error: mmap() syscall returned with (%s)\n",
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strerror_r(errno, sbuf, sizeof(sbuf)));
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goto out_close;
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}
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for (n = 0; n < 6; n++) {
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u64 stamp, now, delta;
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stamp = mmap_read_self(addr);
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for (i = 0; i < loops; i++)
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tmp++;
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now = mmap_read_self(addr);
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loops *= 10;
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delta = now - stamp;
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pr_debug("%14d: %14Lu\n", n, (long long)delta);
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delta_sum += delta;
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}
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munmap(addr, page_size);
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pr_debug(" ");
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out_close:
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close(fd);
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if (!delta_sum)
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return -1;
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return 0;
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}
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int test__rdpmc(void)
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{
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int status = 0;
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int wret = 0;
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int ret;
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int pid;
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pid = fork();
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if (pid < 0)
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return -1;
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if (!pid) {
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ret = __test__rdpmc();
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exit(ret);
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}
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wret = waitpid(pid, &status, 0);
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if (wret < 0 || status)
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return -1;
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return 0;
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}
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#endif
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