Andrew's git / gitweb.git / trace.c
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trace.con commit Merge branch 'cc/perf-bisect' (0264531)
   1/*
   2 * GIT - The information manager from hell
   3 *
   4 * Copyright (C) 2000-2002 Michael R. Elkins <me@mutt.org>
   5 * Copyright (C) 2002-2004 Oswald Buddenhagen <ossi@users.sf.net>
   6 * Copyright (C) 2004 Theodore Y. Ts'o <tytso@mit.edu>
   7 * Copyright (C) 2006 Mike McCormack
   8 * Copyright (C) 2006 Christian Couder
   9 *
  10 *  This program is free software; you can redistribute it and/or modify
  11 *  it under the terms of the GNU General Public License as published by
  12 *  the Free Software Foundation; either version 2 of the License, or
  13 *  (at your option) any later version.
  14 *
  15 *  This program is distributed in the hope that it will be useful,
  16 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 *  GNU General Public License for more details.
  19 *
  20 *  You should have received a copy of the GNU General Public License
  21 *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24#include "cache.h"
  25#include "quote.h"
  26
  27struct trace_key trace_default_key = { "GIT_TRACE", 0, 0, 0 };
  28struct trace_key trace_perf_key = TRACE_KEY_INIT(PERFORMANCE);
  29struct trace_key trace_setup_key = TRACE_KEY_INIT(SETUP);
  30
  31/* Get a trace file descriptor from "key" env variable. */
  32static int get_trace_fd(struct trace_key *key)
  33{
  34        const char *trace;
  35
  36        /* don't open twice */
  37        if (key->initialized)
  38                return key->fd;
  39
  40        trace = getenv(key->key);
  41
  42        if (!trace || !strcmp(trace, "") ||
  43            !strcmp(trace, "0") || !strcasecmp(trace, "false"))
  44                key->fd = 0;
  45        else if (!strcmp(trace, "1") || !strcasecmp(trace, "true"))
  46                key->fd = STDERR_FILENO;
  47        else if (strlen(trace) == 1 && isdigit(*trace))
  48                key->fd = atoi(trace);
  49        else if (is_absolute_path(trace)) {
  50                int fd = open(trace, O_WRONLY | O_APPEND | O_CREAT, 0666);
  51                if (fd == -1) {
  52                        warning("could not open '%s' for tracing: %s",
  53                                trace, strerror(errno));
  54                        trace_disable(key);
  55                } else {
  56                        key->fd = fd;
  57                        key->need_close = 1;
  58                }
  59        } else {
  60                warning("unknown trace value for '%s': %s\n"
  61                        "         If you want to trace into a file, then please set %s\n"
  62                        "         to an absolute pathname (starting with /)",
  63                        key->key, trace, key->key);
  64                trace_disable(key);
  65        }
  66
  67        key->initialized = 1;
  68        return key->fd;
  69}
  70
  71void trace_disable(struct trace_key *key)
  72{
  73        if (key->need_close)
  74                close(key->fd);
  75        key->fd = 0;
  76        key->initialized = 1;
  77        key->need_close = 0;
  78}
  79
  80static int prepare_trace_line(const char *file, int line,
  81                              struct trace_key *key, struct strbuf *buf)
  82{
  83        static struct trace_key trace_bare = TRACE_KEY_INIT(BARE);
  84        struct timeval tv;
  85        struct tm tm;
  86        time_t secs;
  87
  88        if (!trace_want(key))
  89                return 0;
  90
  91        set_try_to_free_routine(NULL);  /* is never reset */
  92
  93        /* unit tests may want to disable additional trace output */
  94        if (trace_want(&trace_bare))
  95                return 1;
  96
  97        /* print current timestamp */
  98        gettimeofday(&tv, NULL);
  99        secs = tv.tv_sec;
 100        localtime_r(&secs, &tm);
 101        strbuf_addf(buf, "%02d:%02d:%02d.%06ld ", tm.tm_hour, tm.tm_min,
 102                    tm.tm_sec, (long) tv.tv_usec);
 103
 104#ifdef HAVE_VARIADIC_MACROS
 105        /* print file:line */
 106        strbuf_addf(buf, "%s:%d ", file, line);
 107        /* align trace output (column 40 catches most files names in git) */
 108        while (buf->len < 40)
 109                strbuf_addch(buf, ' ');
 110#endif
 111
 112        return 1;
 113}
 114
 115static void trace_write(struct trace_key *key, const void *buf, unsigned len)
 116{
 117        if (write_in_full(get_trace_fd(key), buf, len) < 0) {
 118                warning("unable to write trace for %s: %s",
 119                        key->key, strerror(errno));
 120                trace_disable(key);
 121        }
 122}
 123
 124void trace_verbatim(struct trace_key *key, const void *buf, unsigned len)
 125{
 126        if (!trace_want(key))
 127                return;
 128        trace_write(key, buf, len);
 129}
 130
 131static void print_trace_line(struct trace_key *key, struct strbuf *buf)
 132{
 133        strbuf_complete_line(buf);
 134        trace_write(key, buf->buf, buf->len);
 135}
 136
 137static void trace_vprintf_fl(const char *file, int line, struct trace_key *key,
 138                             const char *format, va_list ap)
 139{
 140        struct strbuf buf = STRBUF_INIT;
 141
 142        if (!prepare_trace_line(file, line, key, &buf))
 143                return;
 144
 145        strbuf_vaddf(&buf, format, ap);
 146        print_trace_line(key, &buf);
 147        strbuf_release(&buf);
 148}
 149
 150static void trace_argv_vprintf_fl(const char *file, int line,
 151                                  const char **argv, const char *format,
 152                                  va_list ap)
 153{
 154        struct strbuf buf = STRBUF_INIT;
 155
 156        if (!prepare_trace_line(file, line, &trace_default_key, &buf))
 157                return;
 158
 159        strbuf_vaddf(&buf, format, ap);
 160
 161        sq_quote_argv_pretty(&buf, argv);
 162        print_trace_line(&trace_default_key, &buf);
 163        strbuf_release(&buf);
 164}
 165
 166void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
 167                     const struct strbuf *data)
 168{
 169        struct strbuf buf = STRBUF_INIT;
 170
 171        if (!prepare_trace_line(file, line, key, &buf))
 172                return;
 173
 174        strbuf_addbuf(&buf, data);
 175        print_trace_line(key, &buf);
 176        strbuf_release(&buf);
 177}
 178
 179static void trace_performance_vprintf_fl(const char *file, int line,
 180                                         uint64_t nanos, const char *format,
 181                                         va_list ap)
 182{
 183        struct strbuf buf = STRBUF_INIT;
 184
 185        if (!prepare_trace_line(file, line, &trace_perf_key, &buf))
 186                return;
 187
 188        strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);
 189
 190        if (format && *format) {
 191                strbuf_addstr(&buf, ": ");
 192                strbuf_vaddf(&buf, format, ap);
 193        }
 194
 195        print_trace_line(&trace_perf_key, &buf);
 196        strbuf_release(&buf);
 197}
 198
 199#ifndef HAVE_VARIADIC_MACROS
 200
 201void trace_printf(const char *format, ...)
 202{
 203        va_list ap;
 204        va_start(ap, format);
 205        trace_vprintf_fl(NULL, 0, &trace_default_key, format, ap);
 206        va_end(ap);
 207}
 208
 209void trace_printf_key(struct trace_key *key, const char *format, ...)
 210{
 211        va_list ap;
 212        va_start(ap, format);
 213        trace_vprintf_fl(NULL, 0, key, format, ap);
 214        va_end(ap);
 215}
 216
 217void trace_argv_printf(const char **argv, const char *format, ...)
 218{
 219        va_list ap;
 220        va_start(ap, format);
 221        trace_argv_vprintf_fl(NULL, 0, argv, format, ap);
 222        va_end(ap);
 223}
 224
 225void trace_strbuf(struct trace_key *key, const struct strbuf *data)
 226{
 227        trace_strbuf_fl(NULL, 0, key, data);
 228}
 229
 230void trace_performance(uint64_t nanos, const char *format, ...)
 231{
 232        va_list ap;
 233        va_start(ap, format);
 234        trace_performance_vprintf_fl(NULL, 0, nanos, format, ap);
 235        va_end(ap);
 236}
 237
 238void trace_performance_since(uint64_t start, const char *format, ...)
 239{
 240        va_list ap;
 241        va_start(ap, format);
 242        trace_performance_vprintf_fl(NULL, 0, getnanotime() - start,
 243                                     format, ap);
 244        va_end(ap);
 245}
 246
 247#else
 248
 249void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
 250                         const char *format, ...)
 251{
 252        va_list ap;
 253        va_start(ap, format);
 254        trace_vprintf_fl(file, line, key, format, ap);
 255        va_end(ap);
 256}
 257
 258void trace_argv_printf_fl(const char *file, int line, const char **argv,
 259                          const char *format, ...)
 260{
 261        va_list ap;
 262        va_start(ap, format);
 263        trace_argv_vprintf_fl(file, line, argv, format, ap);
 264        va_end(ap);
 265}
 266
 267void trace_performance_fl(const char *file, int line, uint64_t nanos,
 268                              const char *format, ...)
 269{
 270        va_list ap;
 271        va_start(ap, format);
 272        trace_performance_vprintf_fl(file, line, nanos, format, ap);
 273        va_end(ap);
 274}
 275
 276#endif /* HAVE_VARIADIC_MACROS */
 277
 278
 279static const char *quote_crnl(const char *path)
 280{
 281        static struct strbuf new_path = STRBUF_INIT;
 282
 283        if (!path)
 284                return NULL;
 285
 286        strbuf_reset(&new_path);
 287
 288        while (*path) {
 289                switch (*path) {
 290                case '\\': strbuf_addstr(&new_path, "\\\\"); break;
 291                case '\n': strbuf_addstr(&new_path, "\\n"); break;
 292                case '\r': strbuf_addstr(&new_path, "\\r"); break;
 293                default:
 294                        strbuf_addch(&new_path, *path);
 295                }
 296                path++;
 297        }
 298        return new_path.buf;
 299}
 300
 301/* FIXME: move prefix to startup_info struct and get rid of this arg */
 302void trace_repo_setup(const char *prefix)
 303{
 304        const char *git_work_tree;
 305        char *cwd;
 306
 307        if (!trace_want(&trace_setup_key))
 308                return;
 309
 310        cwd = xgetcwd();
 311
 312        if (!(git_work_tree = get_git_work_tree()))
 313                git_work_tree = "(null)";
 314
 315        if (!prefix)
 316                prefix = "(null)";
 317
 318        trace_printf_key(&trace_setup_key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));
 319        trace_printf_key(&trace_setup_key, "setup: git_common_dir: %s\n", quote_crnl(get_git_common_dir()));
 320        trace_printf_key(&trace_setup_key, "setup: worktree: %s\n", quote_crnl(git_work_tree));
 321        trace_printf_key(&trace_setup_key, "setup: cwd: %s\n", quote_crnl(cwd));
 322        trace_printf_key(&trace_setup_key, "setup: prefix: %s\n", quote_crnl(prefix));
 323
 324        free(cwd);
 325}
 326
 327int trace_want(struct trace_key *key)
 328{
 329        return !!get_trace_fd(key);
 330}
 331
 332#if defined(HAVE_CLOCK_GETTIME) && defined(HAVE_CLOCK_MONOTONIC)
 333
 334static inline uint64_t highres_nanos(void)
 335{
 336        struct timespec ts;
 337        if (clock_gettime(CLOCK_MONOTONIC, &ts))
 338                return 0;
 339        return (uint64_t) ts.tv_sec * 1000000000 + ts.tv_nsec;
 340}
 341
 342#elif defined (GIT_WINDOWS_NATIVE)
 343
 344static inline uint64_t highres_nanos(void)
 345{
 346        static uint64_t high_ns, scaled_low_ns;
 347        static int scale;
 348        LARGE_INTEGER cnt;
 349
 350        if (!scale) {
 351                if (!QueryPerformanceFrequency(&cnt))
 352                        return 0;
 353
 354                /* high_ns = number of ns per cnt.HighPart */
 355                high_ns = (1000000000LL << 32) / (uint64_t) cnt.QuadPart;
 356
 357                /*
 358                 * Number of ns per cnt.LowPart is 10^9 / frequency (or
 359                 * high_ns >> 32). For maximum precision, we scale this factor
 360                 * so that it just fits within 32 bit (i.e. won't overflow if
 361                 * multiplied with cnt.LowPart).
 362                 */
 363                scaled_low_ns = high_ns;
 364                scale = 32;
 365                while (scaled_low_ns >= 0x100000000LL) {
 366                        scaled_low_ns >>= 1;
 367                        scale--;
 368                }
 369        }
 370
 371        /* if QPF worked on initialization, we expect QPC to work as well */
 372        QueryPerformanceCounter(&cnt);
 373
 374        return (high_ns * cnt.HighPart) +
 375               ((scaled_low_ns * cnt.LowPart) >> scale);
 376}
 377
 378#else
 379# define highres_nanos() 0
 380#endif
 381
 382static inline uint64_t gettimeofday_nanos(void)
 383{
 384        struct timeval tv;
 385        gettimeofday(&tv, NULL);
 386        return (uint64_t) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
 387}
 388
 389/*
 390 * Returns nanoseconds since the epoch (01/01/1970), for performance tracing
 391 * (i.e. favoring high precision over wall clock time accuracy).
 392 */
 393uint64_t getnanotime(void)
 394{
 395        static uint64_t offset;
 396        if (offset > 1) {
 397                /* initialization succeeded, return offset + high res time */
 398                return offset + highres_nanos();
 399        } else if (offset == 1) {
 400                /* initialization failed, fall back to gettimeofday */
 401                return gettimeofday_nanos();
 402        } else {
 403                /* initialize offset if high resolution timer works */
 404                uint64_t now = gettimeofday_nanos();
 405                uint64_t highres = highres_nanos();
 406                if (highres)
 407                        offset = now - highres;
 408                else
 409                        offset = 1;
 410                return now;
 411        }
 412}
 413
 414static uint64_t command_start_time;
 415static struct strbuf command_line = STRBUF_INIT;
 416
 417static void print_command_performance_atexit(void)
 418{
 419        trace_performance_since(command_start_time, "git command:%s",
 420                                command_line.buf);
 421}
 422
 423void trace_command_performance(const char **argv)
 424{
 425        if (!trace_want(&trace_perf_key))
 426                return;
 427
 428        if (!command_start_time)
 429                atexit(print_command_performance_atexit);
 430
 431        strbuf_reset(&command_line);
 432        sq_quote_argv_pretty(&command_line, argv);
 433        command_start_time = getnanotime();
 434}