2 * Written by Josh Dybnis and released to the public domain, as explained at
3 * http://creativecommons.org/licenses/publicdomain
13 #define LWT_BUFFER_SCALE 20
14 #define LWT_BUFFER_SIZE (1ULL << LWT_BUFFER_SCALE)
15 #define LWT_BUFFER_MASK (LWT_BUFFER_SIZE - 1)
17 volatile int halt_ = 0;
19 typedef struct lwt_record {
26 typedef struct lwt_buffer {
31 lwt_buffer_t *TraceBuffer[MAX_NUM_THREADS] = {};
32 char TraceLevel[256] = {};
33 static const char *TraceSpec = "";
35 void lwt_thread_init (void) {
36 int thread_index = GET_THREAD_INDEX();
38 if (TraceBuffer[thread_index] == NULL) {
39 TraceBuffer[thread_index] =
40 (lwt_buffer_t *)nbd_malloc(sizeof(lwt_buffer_t) + sizeof(lwt_record_t) * LWT_BUFFER_SIZE);
41 memset(TraceBuffer[thread_index], 0, sizeof(lwt_buffer_t));
45 void lwt_set_trace_level (const char *flags) {
46 assert(strlen(flags) % 2 == 0); // a well formed <flags> should be an even number of characters long
48 memset(TraceLevel, 0, sizeof(TraceLevel));
49 for (int i = 0; flags[i]; i+=2) {
50 TraceLevel[(unsigned)flags[i]] = flags[i+1];
54 static void dump_record (FILE *file, int thread_id, lwt_record_t *r, uint64_t offset) {
55 // print the record if its trace category is enabled at a high enough level
56 int flag = r->format >> 56;
57 int level = (r->format >> 48) & 0xFF;
58 if (TraceLevel[(unsigned)flag] >= level) {
59 char s[3] = {flag, level, '\0'};
60 fprintf(file, "%09llu %d %s ", ((uint64_t)r->timestamp - offset) >> 5, thread_id, s);
61 const char *format = (const char *)(size_t)(r->format & MASK(48)); // strip out the embedded flags
62 fprintf(file, format, r->value1, r->value2);
67 static void dump_buffer (FILE *file, int thread_index, uint64_t offset) {
68 lwt_buffer_t *tb = TraceBuffer[thread_index];
70 if (tb->head > LWT_BUFFER_SIZE) {
71 for (int i = tb->head & LWT_BUFFER_MASK; i < LWT_BUFFER_SIZE; ++i) {
72 dump_record(file, thread_index + 1, tb->x + i, offset);
76 for (int i = 0; i < (tb->head & LWT_BUFFER_MASK); ++i) {
77 dump_record(file, thread_index + 1, tb->x + i, offset);
81 void lwt_halt (void) {
85 void lwt_dump (const char *file_name) {
87 uint64_t offset = (uint64_t)-1;
89 for (int i = 0; i < MAX_NUM_THREADS; ++i) {
90 if (TraceBuffer[i] != NULL && TraceBuffer[i]->head != 0) {
91 uint64_t x = TraceBuffer[i]->x[0].timestamp;
95 if (TraceBuffer[i]->head > LWT_BUFFER_SIZE)
97 x = TraceBuffer[i]->x[TraceBuffer[i]->head & LWT_BUFFER_MASK].timestamp;
105 if (offset != (uint64_t)-1) {
106 FILE *file = fopen(file_name, "w");
108 for (int i = 0; i < MAX_NUM_THREADS; ++i) {
109 if (TraceBuffer[i] != NULL) {
110 dump_buffer(file, i, offset);
118 void lwt_trace_i (uint64_t format, size_t value1, size_t value2) {
120 lwt_buffer_t *tb = TraceBuffer[GET_THREAD_INDEX()];
123 __asm__ __volatile__("rdtsc" : "=a" (l), "=d" (u));
124 uint64_t timestamp = ((uint64_t)u << 32) | l;
125 lwt_record_t temp = { timestamp, format, value1, value2 };
127 tb->x[tb->head++ & LWT_BUFFER_MASK] = temp;