perf_self_monitor: 32-bit and other improvements

Signed-off-by: Andy Lutomirski <luto@kernel.org>

1 files changed, 29 insertions, 1 deletions

diff --git a/tight_loop/perf_self_monitor.c b/tight_loop/perf_self_monitor.c
index 378d0fd..51c3338 100644
--- a/tight_loop/perf_self_monitor.c
+++ b/tight_loop/perf_self_monitor.c
@@ -156,9 +156,32 @@ bool psm_atomic_sample_enosys(uint64_t *count,
 			      const struct psm_counter *ctr, void *opaque)
 {
 	struct psm_atomic duration = psm_atomic_start(ctr);
+#ifdef __x86_64__
 	unsigned long rax;
 	rax = 0xbfffffff;
 	asm volatile ("syscall" : "+a" (rax) : : "rcx", "r11");
+#else
+	syscall(0x3fffffff);
+#endif
+	return psm_atomic_elapsed(count, &duration, ctr);
+}
+
+bool psm_atomic_sample_bad_prctl_x1000(uint64_t *count,
+			      const struct psm_counter *ctr, void *opaque)
+{
+	struct psm_atomic duration = psm_atomic_start(ctr);
+#ifdef __x86_64__
+	unsigned long rax;
+	register unsigned long rdi asm("rdi");
+	for (int i = 0; i < 1000; i++) {
+		rax = SYS_prctl;
+		rdi = -1;
+		asm volatile ("syscall" : "+a" (rax), "+r" (rdi) : : "rcx", "r11");
+	}
+#else
+	for (int i = 0; i < 1000; i++)
+		syscall(SYS_prctl, -1);
+#endif
 	return psm_atomic_elapsed(count, &duration, ctr);
 }
 
@@ -235,7 +258,12 @@ int main()
 
 	for (int i = 0; i < 20; i++) {
 		uint64_t cost = psm_integer_quantile(ctr, psm_atomic_sample_enosys, NULL, 250, 500) - baseline;
-		printf("%llu\n", (unsigned long long)cost);
+		printf("1x ENOSYS: %llu\n", (unsigned long long)cost);
+	}
+
+	for (int i = 0; i < 20; i++) {
+		uint64_t cost = psm_integer_quantile(ctr, psm_atomic_sample_bad_prctl_x1000, NULL, 250, 500) - baseline;
+		printf("1000x bad prctl: %llu\n", (unsigned long long)cost/1000);
 	}
 
 	psm_counter_destroy(ctr);