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authorLluís <xscript@gmx.net>2011-08-31 20:30:57 +0200
committerStefan Hajnoczi <stefanha@linux.vnet.ibm.com>2011-09-01 10:34:53 +0100
commitedb47ec498a5c00607e8d428668d5141822a9eac (patch)
tree3e1e9edc6ddfae6e34c132f16ec04fe32eb5335d /trace
parent09001ee7b27b9b5f049362efc427d03e2186a431 (diff)
trace: move backend-specific code into the trace/ directory
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Diffstat (limited to 'trace')
-rw-r--r--trace/simple.c355
-rw-r--r--trace/simple.h48
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 */