diff options
Diffstat (limited to 'trace')
| -rw-r--r-- | trace/simple.c | 355 | ||||
| -rw-r--r-- | trace/simple.h | 48 |
2 files changed, 403 insertions, 0 deletions
diff --git a/trace/simple.c b/trace/simple.c new file mode 100644 index 0000000000..de355e9675 --- /dev/null +++ b/trace/simple.c @@ -0,0 +1,355 @@ +/* + * Simple trace backend + * + * Copyright IBM, Corp. 2010 + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + * + */ + +#include <stdlib.h> +#include <stdint.h> +#include <stdio.h> +#include <time.h> +#include <signal.h> +#include <pthread.h> +#include "qemu-timer.h" +#include "trace.h" + +/** Trace file header event ID */ +#define HEADER_EVENT_ID (~(uint64_t)0) /* avoids conflicting with TraceEventIDs */ + +/** Trace file magic number */ +#define HEADER_MAGIC 0xf2b177cb0aa429b4ULL + +/** Trace file version number, bump if format changes */ +#define HEADER_VERSION 0 + +/** Records were dropped event ID */ +#define DROPPED_EVENT_ID (~(uint64_t)0 - 1) + +/** Trace record is valid */ +#define TRACE_RECORD_VALID ((uint64_t)1 << 63) + +/** Trace buffer entry */ +typedef struct { + uint64_t event; + uint64_t timestamp_ns; + uint64_t x1; + uint64_t x2; + uint64_t x3; + uint64_t x4; + uint64_t x5; + uint64_t x6; +} TraceRecord; + +enum { + TRACE_BUF_LEN = 4096, + TRACE_BUF_FLUSH_THRESHOLD = TRACE_BUF_LEN / 4, +}; + +/* + * Trace records are written out by a dedicated thread. The thread waits for + * records to become available, writes them out, and then waits again. + */ +static pthread_mutex_t trace_lock = PTHREAD_MUTEX_INITIALIZER; +static pthread_cond_t trace_available_cond = PTHREAD_COND_INITIALIZER; +static pthread_cond_t trace_empty_cond = PTHREAD_COND_INITIALIZER; +static bool trace_available; +static bool trace_writeout_enabled; + +static TraceRecord trace_buf[TRACE_BUF_LEN]; +static unsigned int trace_idx; +static FILE *trace_fp; +static char *trace_file_name = NULL; + +/** + * Read a trace record from the trace buffer + * + * @idx Trace buffer index + * @record Trace record to fill + * + * Returns false if the record is not valid. + */ +static bool get_trace_record(unsigned int idx, TraceRecord *record) +{ + if (!(trace_buf[idx].event & TRACE_RECORD_VALID)) { + return false; + } + + __sync_synchronize(); /* read memory barrier before accessing record */ + + *record = trace_buf[idx]; + record->event &= ~TRACE_RECORD_VALID; + return true; +} + +/** + * Kick writeout thread + * + * @wait Whether to wait for writeout thread to complete + */ +static void flush_trace_file(bool wait) +{ + pthread_mutex_lock(&trace_lock); + trace_available = true; + pthread_cond_signal(&trace_available_cond); + + if (wait) { + pthread_cond_wait(&trace_empty_cond, &trace_lock); + } + + pthread_mutex_unlock(&trace_lock); +} + +static void wait_for_trace_records_available(void) +{ + pthread_mutex_lock(&trace_lock); + while (!(trace_available && trace_writeout_enabled)) { + pthread_cond_signal(&trace_empty_cond); + pthread_cond_wait(&trace_available_cond, &trace_lock); + } + trace_available = false; + pthread_mutex_unlock(&trace_lock); +} + +static void *writeout_thread(void *opaque) +{ + TraceRecord record; + unsigned int writeout_idx = 0; + unsigned int num_available, idx; + size_t unused __attribute__ ((unused)); + + for (;;) { + wait_for_trace_records_available(); + + num_available = trace_idx - writeout_idx; + if (num_available > TRACE_BUF_LEN) { + record = (TraceRecord){ + .event = DROPPED_EVENT_ID, + .x1 = num_available, + }; + unused = fwrite(&record, sizeof(record), 1, trace_fp); + writeout_idx += num_available; + } + + idx = writeout_idx % TRACE_BUF_LEN; + while (get_trace_record(idx, &record)) { + trace_buf[idx].event = 0; /* clear valid bit */ + unused = fwrite(&record, sizeof(record), 1, trace_fp); + idx = ++writeout_idx % TRACE_BUF_LEN; + } + + fflush(trace_fp); + } + return NULL; +} + +static void trace(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, + uint64_t x4, uint64_t x5, uint64_t x6) +{ + unsigned int idx; + uint64_t timestamp; + + if (!trace_list[event].state) { + return; + } + + timestamp = get_clock(); + + idx = __sync_fetch_and_add(&trace_idx, 1) % TRACE_BUF_LEN; + trace_buf[idx] = (TraceRecord){ + .event = event, + .timestamp_ns = timestamp, + .x1 = x1, + .x2 = x2, + .x3 = x3, + .x4 = x4, + .x5 = x5, + .x6 = x6, + }; + __sync_synchronize(); /* write barrier before marking as valid */ + trace_buf[idx].event |= TRACE_RECORD_VALID; + + if ((idx + 1) % TRACE_BUF_FLUSH_THRESHOLD == 0) { + flush_trace_file(false); + } +} + +void trace0(TraceEventID event) +{ + trace(event, 0, 0, 0, 0, 0, 0); +} + +void trace1(TraceEventID event, uint64_t x1) +{ + trace(event, x1, 0, 0, 0, 0, 0); +} + +void trace2(TraceEventID event, uint64_t x1, uint64_t x2) +{ + trace(event, x1, x2, 0, 0, 0, 0); +} + +void trace3(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3) +{ + trace(event, x1, x2, x3, 0, 0, 0); +} + +void trace4(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4) +{ + trace(event, x1, x2, x3, x4, 0, 0); +} + +void trace5(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4, uint64_t x5) +{ + trace(event, x1, x2, x3, x4, x5, 0); +} + +void trace6(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4, uint64_t x5, uint64_t x6) +{ + trace(event, x1, x2, x3, x4, x5, x6); +} + +void st_set_trace_file_enabled(bool enable) +{ + if (enable == !!trace_fp) { + return; /* no change */ + } + + /* Halt trace writeout */ + flush_trace_file(true); + trace_writeout_enabled = false; + flush_trace_file(true); + + if (enable) { + static const TraceRecord header = { + .event = HEADER_EVENT_ID, + .timestamp_ns = HEADER_MAGIC, + .x1 = HEADER_VERSION, + }; + + trace_fp = fopen(trace_file_name, "w"); + if (!trace_fp) { + return; + } + + if (fwrite(&header, sizeof header, 1, trace_fp) != 1) { + fclose(trace_fp); + trace_fp = NULL; + return; + } + + /* Resume trace writeout */ + trace_writeout_enabled = true; + flush_trace_file(false); + } else { + fclose(trace_fp); + trace_fp = NULL; + } +} + +/** + * Set the name of a trace file + * + * @file The trace file name or NULL for the default name-<pid> set at + * config time + */ +bool st_set_trace_file(const char *file) +{ + st_set_trace_file_enabled(false); + + free(trace_file_name); + + if (!file) { + if (asprintf(&trace_file_name, CONFIG_TRACE_FILE, getpid()) < 0) { + trace_file_name = NULL; + return false; + } + } else { + if (asprintf(&trace_file_name, "%s", file) < 0) { + trace_file_name = NULL; + return false; + } + } + + st_set_trace_file_enabled(true); + return true; +} + +void st_print_trace_file_status(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...)) +{ + stream_printf(stream, "Trace file \"%s\" %s.\n", + trace_file_name, trace_fp ? "on" : "off"); +} + +void st_print_trace(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...)) +{ + unsigned int i; + + for (i = 0; i < TRACE_BUF_LEN; i++) { + TraceRecord record; + + if (!get_trace_record(i, &record)) { + continue; + } + stream_printf(stream, "Event %" PRIu64 " : %" PRIx64 " %" PRIx64 + " %" PRIx64 " %" PRIx64 " %" PRIx64 " %" PRIx64 "\n", + record.event, record.x1, record.x2, + record.x3, record.x4, record.x5, + record.x6); + } +} + +void st_print_trace_events(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...)) +{ + unsigned int i; + + for (i = 0; i < NR_TRACE_EVENTS; i++) { + stream_printf(stream, "%s [Event ID %u] : state %u\n", + trace_list[i].tp_name, i, trace_list[i].state); + } +} + +bool st_change_trace_event_state(const char *name, bool enabled) +{ + unsigned int i; + + for (i = 0; i < NR_TRACE_EVENTS; i++) { + if (!strcmp(trace_list[i].tp_name, name)) { + trace_list[i].state = enabled; + return true; + } + } + return false; +} + +void st_flush_trace_buffer(void) +{ + flush_trace_file(true); +} + +bool st_init(const char *file) +{ + pthread_t thread; + pthread_attr_t attr; + sigset_t set, oldset; + int ret; + + pthread_attr_init(&attr); + pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); + + sigfillset(&set); + pthread_sigmask(SIG_SETMASK, &set, &oldset); + ret = pthread_create(&thread, &attr, writeout_thread, NULL); + pthread_sigmask(SIG_SETMASK, &oldset, NULL); + + if (ret != 0) { + return false; + } + + atexit(st_flush_trace_buffer); + st_set_trace_file(file); + return true; +} diff --git a/trace/simple.h b/trace/simple.h new file mode 100644 index 0000000000..77633ab68a --- /dev/null +++ b/trace/simple.h @@ -0,0 +1,48 @@ +/* + * Simple trace backend + * + * Copyright IBM, Corp. 2010 + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + * + */ + +#ifndef TRACE_SIMPLE_H +#define TRACE_SIMPLE_H + +#include <stdint.h> +#include <stdbool.h> +#include <stdio.h> + +#ifdef CONFIG_TRACE_SIMPLE +typedef uint64_t TraceEventID; + +typedef struct { + const char *tp_name; + bool state; +} TraceEvent; + +void trace0(TraceEventID event); +void trace1(TraceEventID event, uint64_t x1); +void trace2(TraceEventID event, uint64_t x1, uint64_t x2); +void trace3(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3); +void trace4(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4); +void trace5(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4, uint64_t x5); +void trace6(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4, uint64_t x5, uint64_t x6); +void st_print_trace(FILE *stream, fprintf_function stream_printf); +void st_print_trace_events(FILE *stream, fprintf_function stream_printf); +bool st_change_trace_event_state(const char *tname, bool tstate); +void st_print_trace_file_status(FILE *stream, fprintf_function stream_printf); +void st_set_trace_file_enabled(bool enable); +bool st_set_trace_file(const char *file); +void st_flush_trace_buffer(void); +bool st_init(const char *file); +#else +static inline bool st_init(const char *file) +{ + return true; +} +#endif /* !CONFIG_TRACE_SIMPLE */ + +#endif /* TRACE_SIMPLE_H */ |