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-rw-r--r--tools/perf/util/tsc.c112
1 files changed, 112 insertions, 0 deletions
diff --git a/tools/perf/util/tsc.c b/tools/perf/util/tsc.c
new file mode 100644
index 000000000..62b4c75c9
--- /dev/null
+++ b/tools/perf/util/tsc.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <errno.h>
+
+#include <linux/compiler.h>
+#include <linux/perf_event.h>
+#include <linux/stddef.h>
+#include <linux/types.h>
+
+#include <asm/barrier.h>
+
+#include "event.h"
+#include "synthetic-events.h"
+#include "debug.h"
+#include "tsc.h"
+
+u64 perf_time_to_tsc(u64 ns, struct perf_tsc_conversion *tc)
+{
+ u64 t, quot, rem;
+
+ t = ns - tc->time_zero;
+ quot = t / tc->time_mult;
+ rem = t % tc->time_mult;
+ return (quot << tc->time_shift) +
+ (rem << tc->time_shift) / tc->time_mult;
+}
+
+u64 tsc_to_perf_time(u64 cyc, struct perf_tsc_conversion *tc)
+{
+ u64 quot, rem;
+
+ if (tc->cap_user_time_short)
+ cyc = tc->time_cycles +
+ ((cyc - tc->time_cycles) & tc->time_mask);
+
+ quot = cyc >> tc->time_shift;
+ rem = cyc & (((u64)1 << tc->time_shift) - 1);
+ return tc->time_zero + quot * tc->time_mult +
+ ((rem * tc->time_mult) >> tc->time_shift);
+}
+
+int perf_read_tsc_conversion(const struct perf_event_mmap_page *pc,
+ struct perf_tsc_conversion *tc)
+{
+ u32 seq;
+ int i = 0;
+
+ while (1) {
+ seq = pc->lock;
+ rmb();
+ tc->time_mult = pc->time_mult;
+ tc->time_shift = pc->time_shift;
+ tc->time_zero = pc->time_zero;
+ tc->time_cycles = pc->time_cycles;
+ tc->time_mask = pc->time_mask;
+ tc->cap_user_time_zero = pc->cap_user_time_zero;
+ tc->cap_user_time_short = pc->cap_user_time_short;
+ rmb();
+ if (pc->lock == seq && !(seq & 1))
+ break;
+ if (++i > 10000) {
+ pr_debug("failed to get perf_event_mmap_page lock\n");
+ return -EINVAL;
+ }
+ }
+
+ if (!tc->cap_user_time_zero)
+ return -EOPNOTSUPP;
+
+ return 0;
+}
+
+int perf_event__synth_time_conv(const struct perf_event_mmap_page *pc,
+ struct perf_tool *tool,
+ perf_event__handler_t process,
+ struct machine *machine)
+{
+ union perf_event event = {
+ .time_conv = {
+ .header = {
+ .type = PERF_RECORD_TIME_CONV,
+ .size = sizeof(struct perf_record_time_conv),
+ },
+ },
+ };
+ struct perf_tsc_conversion tc;
+ int err;
+
+ if (!pc)
+ return 0;
+ err = perf_read_tsc_conversion(pc, &tc);
+ if (err == -EOPNOTSUPP)
+ return 0;
+ if (err)
+ return err;
+
+ pr_debug2("Synthesizing TSC conversion information\n");
+
+ event.time_conv.time_mult = tc.time_mult;
+ event.time_conv.time_shift = tc.time_shift;
+ event.time_conv.time_zero = tc.time_zero;
+ event.time_conv.time_cycles = tc.time_cycles;
+ event.time_conv.time_mask = tc.time_mask;
+ event.time_conv.cap_user_time_zero = tc.cap_user_time_zero;
+ event.time_conv.cap_user_time_short = tc.cap_user_time_short;
+
+ return process(tool, &event, NULL, machine);
+}
+
+u64 __weak rdtsc(void)
+{
+ return 0;
+}