Messages in this thread Patch in this message | | | From | Adrian Hunter <> | Subject | [PATCH V2 6/8] perf jit: Add support for using TSC as a timestamp | Date | Tue, 8 Mar 2016 10:38:50 +0200 |
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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@intel.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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