[tip:perf/core] perf jit: Add support for using TSC as a timestamp

From: tip-bot for Adrian Hunter
Date: Wed Apr 06 2016 - 03:09:30 EST

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Commit-ID: 2a28e23049af99e1c810111ef5e56455cafeda45
Gitweb: http://git.kernel.org/tip/2a28e23049af99e1c810111ef5e56455cafeda45
Author: Adrian Hunter <adrian.hunter@xxxxxxxxx>
AuthorDate: Tue, 8 Mar 2016 10:38:50 +0200
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Fri, 1 Apr 2016 18:42:55 -0300

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@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: He Kuang <hekuang@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1457426330-30226-1-git-send-email-adrian.hunter@xxxxxxxxx
[ Added the fixup from He Kuang to make it build on other arches, ]
[ such as aarch64, to avoid inserting this bisectiong breakage upstream ]
Link: http://lkml.kernel.org/r/1459482572-129494-1-git-send-email-hekuang@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/arch/x86/util/tsc.c | 1 -
tools/perf/arch/x86/util/tsc.h | 17 -----------------
tools/perf/jvmti/jvmti_agent.c | 43 ++++++++++++++++++++++++++++++++++++++++--
tools/perf/util/Build | 3 +--
tools/perf/util/jitdump.c | 37 +++++++++++++++++++++++++++++++-----
tools/perf/util/jitdump.h | 3 +++
tools/perf/util/tsc.h | 11 ++++++++++-
7 files changed, 87 insertions(+), 28 deletions(-)

diff --git a/tools/perf/arch/x86/util/tsc.c b/tools/perf/arch/x86/util/tsc.c
index 70ff7c1..357f1b1 100644
--- a/tools/perf/arch/x86/util/tsc.c
+++ b/tools/perf/arch/x86/util/tsc.c
@@ -7,7 +7,6 @@
#include <linux/types.h>
#include "../../util/debug.h"
#include "../../util/tsc.h"
-#include "tsc.h"

int perf_read_tsc_conversion(const struct perf_event_mmap_page *pc,
struct perf_tsc_conversion *tc)
diff --git a/tools/perf/arch/x86/util/tsc.h b/tools/perf/arch/x86/util/tsc.h
deleted file mode 100644
index 2edc4d3..0000000
--- a/tools/perf/arch/x86/util/tsc.h
+++ /dev/null
@@ -1,17 +0,0 @@
-#ifndef TOOLS_PERF_ARCH_X86_UTIL_TSC_H__
-#define TOOLS_PERF_ARCH_X86_UTIL_TSC_H__
-
-#include <linux/types.h>
-
-struct perf_tsc_conversion {
- u16 time_shift;
- u32 time_mult;
- u64 time_zero;
-};
-
-struct perf_event_mmap_page;
-
-int perf_read_tsc_conversion(const struct perf_event_mmap_page *pc,
- struct perf_tsc_conversion *tc);
-
-#endif /* TOOLS_PERF_ARCH_X86_UTIL_TSC_H__ */
diff --git a/tools/perf/jvmti/jvmti_agent.c b/tools/perf/jvmti/jvmti_agent.c
index 6461e02..3573f31 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/Build b/tools/perf/util/Build
index da48fd8..85ceff3 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -69,8 +69,7 @@ libperf-y += stat-shadow.o
libperf-y += record.o
libperf-y += srcline.o
libperf-y += data.o
-libperf-$(CONFIG_X86) += tsc.o
-libperf-$(CONFIG_AUXTRACE) += tsc.o
+libperf-y += tsc.o
libperf-y += cloexec.o
libperf-y += thread-stack.o
libperf-$(CONFIG_AUXTRACE) += auxtrace.o
diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
index ad0c0bb..52fcef3 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
@@ -499,7 +526,7 @@ 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 b66c1f5..bcacd20 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)

diff --git a/tools/perf/util/tsc.h b/tools/perf/util/tsc.h
index 280ddc0..d5b11e2 100644
--- a/tools/perf/util/tsc.h
+++ b/tools/perf/util/tsc.h
@@ -4,7 +4,16 @@
#include <linux/types.h>

#include "event.h"
-#include "../arch/x86/util/tsc.h"
+
+struct perf_tsc_conversion {
+ u16 time_shift;
+ u32 time_mult;
+ u64 time_zero;
+};
+struct perf_event_mmap_page;
+
+int perf_read_tsc_conversion(const struct perf_event_mmap_page *pc,
+ struct perf_tsc_conversion *tc);

u64 perf_time_to_tsc(u64 ns, struct perf_tsc_conversion *tc);
u64 tsc_to_perf_time(u64 cyc, struct perf_tsc_conversion *tc);

Next message: tip-bot for Arnaldo Carvalho de Melo: "[tip:perf/core] perf trace: Introduce function to set the base timestamp"
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