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Message-Id: <1457426330-30226-1-git-send-email-adrian.hunter@intel.com>
Date: Tue, 8 Mar 2016 10:38:50 +0200
From: Adrian Hunter <adrian.hunter@...el.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Jiri Olsa <jolsa@...hat.com>, linux-kernel@...r.kernel.org,
Stephane Eranian <eranian@...gle.com>
Subject: [PATCH V2 6/8] perf jit: Add support for using TSC as a timestamp
Intel PT uses TSC as a timestamp, so add support for using TSC
instead of the monotonic clock. Use of TSC is selected by
an environment variable "JITDUMP_USE_ARCH_TIMESTAMP" and flagged
in the jitdump file with flag JITDUMP_FLAGS_ARCH_TIMESTAMP.
Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
---
Changes in V2:
Fixed "From" and "Signed-off-by" email addresses
tools/perf/jvmti/jvmti_agent.c | 43 ++++++++++++++++++++++++++++++++++++++++--
tools/perf/util/jitdump.c | 37 +++++++++++++++++++++++++++++++-----
tools/perf/util/jitdump.h | 3 +++
3 files changed, 76 insertions(+), 7 deletions(-)
diff --git a/tools/perf/jvmti/jvmti_agent.c b/tools/perf/jvmti/jvmti_agent.c
index 6461e02ab940..3573f315f955 100644
--- a/tools/perf/jvmti/jvmti_agent.c
+++ b/tools/perf/jvmti/jvmti_agent.c
@@ -92,6 +92,22 @@ error:
return ret;
}
+static int use_arch_timestamp;
+
+static inline uint64_t
+get_arch_timestamp(void)
+{
+#if defined(__i386__) || defined(__x86_64__)
+ unsigned int low, high;
+
+ asm volatile("rdtsc" : "=a" (low), "=d" (high));
+
+ return low | ((uint64_t)high) << 32;
+#else
+ return 0;
+#endif
+}
+
#define NSEC_PER_SEC 1000000000
static int perf_clk_id = CLOCK_MONOTONIC;
@@ -107,6 +123,9 @@ perf_get_timestamp(void)
struct timespec ts;
int ret;
+ if (use_arch_timestamp)
+ return get_arch_timestamp();
+
ret = clock_gettime(perf_clk_id, &ts);
if (ret)
return 0;
@@ -203,6 +222,17 @@ perf_close_marker_file(void)
munmap(marker_addr, pgsz);
}
+static void
+init_arch_timestamp(void)
+{
+ char *str = getenv("JITDUMP_USE_ARCH_TIMESTAMP");
+
+ if (!str || !*str || !strcmp(str, "0"))
+ return;
+
+ use_arch_timestamp = 1;
+}
+
void *jvmti_open(void)
{
int pad_cnt;
@@ -211,11 +241,17 @@ void *jvmti_open(void)
int fd;
FILE *fp;
+ init_arch_timestamp();
+
/*
* check if clockid is supported
*/
- if (!perf_get_timestamp())
- warnx("jvmti: kernel does not support %d clock id", perf_clk_id);
+ if (!perf_get_timestamp()) {
+ if (use_arch_timestamp)
+ warnx("jvmti: arch timestamp not supported");
+ else
+ warnx("jvmti: kernel does not support %d clock id", perf_clk_id);
+ }
memset(&header, 0, sizeof(header));
@@ -263,6 +299,9 @@ void *jvmti_open(void)
header.timestamp = perf_get_timestamp();
+ if (use_arch_timestamp)
+ header.flags |= JITDUMP_FLAGS_ARCH_TIMESTAMP;
+
if (!fwrite(&header, sizeof(header), 1, fp)) {
warn("jvmti: cannot write dumpfile header");
goto error;
diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
index cd272cc21e05..5608179dff34 100644
--- a/tools/perf/util/jitdump.c
+++ b/tools/perf/util/jitdump.c
@@ -17,6 +17,7 @@
#include "strlist.h"
#include <elf.h>
+#include "tsc.h"
#include "session.h"
#include "jit.h"
#include "jitdump.h"
@@ -33,6 +34,7 @@ struct jit_buf_desc {
size_t bufsize;
FILE *in;
bool needs_bswap; /* handles cross-endianess */
+ bool use_arch_timestamp;
void *debug_data;
size_t nr_debug_entries;
uint32_t code_load_count;
@@ -158,13 +160,16 @@ jit_open(struct jit_buf_desc *jd, const char *name)
header.flags = bswap_64(header.flags);
}
+ jd->use_arch_timestamp = header.flags & JITDUMP_FLAGS_ARCH_TIMESTAMP;
+
if (verbose > 2)
- pr_debug("version=%u\nhdr.size=%u\nts=0x%llx\npid=%d\nelf_mach=%d\n",
+ pr_debug("version=%u\nhdr.size=%u\nts=0x%llx\npid=%d\nelf_mach=%d\nuse_arch_timestamp=%d\n",
header.version,
header.total_size,
(unsigned long long)header.timestamp,
header.pid,
- header.elf_mach);
+ header.elf_mach,
+ jd->use_arch_timestamp);
if (header.flags & JITDUMP_FLAGS_RESERVED) {
pr_err("jitdump file contains invalid or unsupported flags 0x%llx\n",
@@ -172,10 +177,15 @@ jit_open(struct jit_buf_desc *jd, const char *name)
goto error;
}
+ if (jd->use_arch_timestamp && !jd->session->time_conv.time_mult) {
+ pr_err("jitdump file uses arch timestamps but there is no timestamp conversion\n");
+ goto error;
+ }
+
/*
* validate event is using the correct clockid
*/
- if (jit_validate_events(jd->session)) {
+ if (!jd->use_arch_timestamp && jit_validate_events(jd->session)) {
pr_err("error, jitted code must be sampled with perf record -k 1\n");
goto error;
}
@@ -329,6 +339,23 @@ jit_inject_event(struct jit_buf_desc *jd, union perf_event *event)
return 0;
}
+static uint64_t convert_timestamp(struct jit_buf_desc *jd, uint64_t timestamp)
+{
+ struct perf_tsc_conversion tc;
+
+ if (!jd->use_arch_timestamp)
+ return timestamp;
+
+ tc.time_shift = jd->session->time_conv.time_shift;
+ tc.time_mult = jd->session->time_conv.time_mult;
+ tc.time_zero = jd->session->time_conv.time_zero;
+
+ if (!tc.time_mult)
+ return 0;
+
+ return tsc_to_perf_time(timestamp, &tc);
+}
+
static int jit_repipe_code_load(struct jit_buf_desc *jd, union jr_entry *jr)
{
struct perf_sample sample;
@@ -410,7 +437,7 @@ static int jit_repipe_code_load(struct jit_buf_desc *jd, union jr_entry *jr)
id->tid = tid;
}
if (jd->sample_type & PERF_SAMPLE_TIME)
- id->time = jr->load.p.timestamp;
+ id->time = convert_timestamp(jd, jr->load.p.timestamp);
/*
* create pseudo sample to induce dso hit increment
@@ -498,7 +525,7 @@ static int jit_repipe_code_move(struct jit_buf_desc *jd, union jr_entry *jr)
id->tid = tid;
}
if (jd->sample_type & PERF_SAMPLE_TIME)
- id->time = jr->load.p.timestamp;
+ id->time = convert_timestamp(jd, jr->load.p.timestamp);
/*
* create pseudo sample to induce dso hit increment
diff --git a/tools/perf/util/jitdump.h b/tools/perf/util/jitdump.h
index b66c1f503d9e..bcacd20d0c1c 100644
--- a/tools/perf/util/jitdump.h
+++ b/tools/perf/util/jitdump.h
@@ -23,9 +23,12 @@
#define JITHEADER_VERSION 1
enum jitdump_flags_bits {
+ JITDUMP_FLAGS_ARCH_TIMESTAMP_BIT,
JITDUMP_FLAGS_MAX_BIT,
};
+#define JITDUMP_FLAGS_ARCH_TIMESTAMP (1ULL << JITDUMP_FLAGS_ARCH_TIMESTAMP_BIT)
+
#define JITDUMP_FLAGS_RESERVED (JITDUMP_FLAGS_MAX_BIT < 64 ? \
(~((1ULL << JITDUMP_FLAGS_MAX_BIT) - 1)) : 0)
--
1.9.1
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