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Diffstat (limited to 'trace2.h')
| -rw-r--r-- | trace2.h | 505 |
1 files changed, 505 insertions, 0 deletions
diff --git a/trace2.h b/trace2.h new file mode 100644 index 0000000000..ede18c2e06 --- /dev/null +++ b/trace2.h @@ -0,0 +1,505 @@ +#ifndef TRACE2_H +#define TRACE2_H + +/** + * The Trace2 API can be used to print debug, performance, and telemetry + * information to stderr or a file. The Trace2 feature is inactive unless + * explicitly enabled by enabling one or more Trace2 Targets. + * + * The Trace2 API is intended to replace the existing (Trace1) + * printf-style tracing provided by the existing `GIT_TRACE` and + * `GIT_TRACE_PERFORMANCE` facilities. During initial implementation, + * Trace2 and Trace1 may operate in parallel. + * + * The Trace2 API defines a set of high-level messages with known fields, + * such as (`start`: `argv`) and (`exit`: {`exit-code`, `elapsed-time`}). + * + * Trace2 instrumentation throughout the Git code base sends Trace2 + * messages to the enabled Trace2 Targets. Targets transform these + * messages content into purpose-specific formats and write events to + * their data streams. In this manner, the Trace2 API can drive + * many different types of analysis. + * + * Targets are defined using a VTable allowing easy extension to other + * formats in the future. This might be used to define a binary format, + * for example. + * + * Trace2 is controlled using `trace2.*` config values in the system and + * global config files and `GIT_TRACE2*` environment variables. Trace2 does + * not read from repo local or worktree config files or respect `-c` + * command line config settings. + * + * For more info about: trace2 targets, conventions for public functions and + * macros, trace2 target formats and examples on trace2 API usage refer to + * Documentation/technical/api-trace2.txt + * + */ + +struct child_process; +struct repository; +struct json_writer; + +/* + * The public TRACE2 routines are grouped into the following groups: + * + * [] trace2_initialize -- initialization. + * [] trace2_cmd_* -- emit command/control messages. + * [] trace2_child* -- emit child start/stop messages. + * [] trace2_exec* -- emit exec start/stop messages. + * [] trace2_thread* -- emit thread start/stop messages. + * [] trace2_def* -- emit definition/parameter mesasges. + * [] trace2_region* -- emit region nesting messages. + * [] trace2_data* -- emit region/thread/repo data messages. + * [] trace2_printf* -- legacy trace[1] messages. + */ + +/* + * Initialize the TRACE2 clock and do nothing else, in particular + * no mallocs, no system inspection, and no environment inspection. + * + * This should be called at the very top of main() to capture the + * process start time. This is intended to reduce chicken-n-egg + * bootstrap pressure. + * + * It is safe to call this more than once. This allows capturing + * absolute startup costs on Windows which uses a little trickery + * to do setup work before common-main.c:main() is called. + * + * The main trace2_initialize_fl() may be called a little later + * after more infrastructure is established. + */ +void trace2_initialize_clock(void); + +/* + * Initialize TRACE2 tracing facility if any of the builtin TRACE2 + * targets are enabled in the system config or the environment. + * This includes setting up the Trace2 thread local storage (TLS). + * Emits a 'version' message containing the version of git + * and the Trace2 protocol. + * + * This function should be called from `main()` as early as possible in + * the life of the process after essential process initialization. + * + * Cleanup/Termination is handled automatically by a registered + * atexit() routine. + */ +void trace2_initialize_fl(const char *file, int line); + +#define trace2_initialize() trace2_initialize_fl(__FILE__, __LINE__) + +/* + * Return 1 if trace2 is enabled (at least one target is active). + */ +int trace2_is_enabled(void); + +/* + * Emit a 'start' event with the original (unmodified) argv. + */ +void trace2_cmd_start_fl(const char *file, int line, const char **argv); + +#define trace2_cmd_start(argv) trace2_cmd_start_fl(__FILE__, __LINE__, (argv)) + +/* + * Emit an 'exit' event. + * + * Write the exit-code that will be passed to exit() or returned + * from main(). + * + * Use this prior to actually calling exit(). + * See "#define exit()" in git-compat-util.h + */ +int trace2_cmd_exit_fl(const char *file, int line, int code); + +#define trace2_cmd_exit(code) (trace2_cmd_exit_fl(__FILE__, __LINE__, (code))) + +/* + * Emit an 'error' event. + * + * Write an error message to the TRACE2 targets. + */ +void trace2_cmd_error_va_fl(const char *file, int line, const char *fmt, + va_list ap); + +#define trace2_cmd_error_va(fmt, ap) \ + trace2_cmd_error_va_fl(__FILE__, __LINE__, (fmt), (ap)) + +/* + * Emit a 'pathname' event with the canonical pathname of the current process + * This gives post-processors a simple field to identify the command without + * having to parse the argv. For example, to distinguish invocations from + * installed versus debug executables. + */ +void trace2_cmd_path_fl(const char *file, int line, const char *pathname); + +#define trace2_cmd_path(p) trace2_cmd_path_fl(__FILE__, __LINE__, (p)) + +/* + * Emit a 'cmd_name' event with the canonical name of the command. + * This gives post-processors a simple field to identify the command + * without having to parse the argv. + */ +void trace2_cmd_name_fl(const char *file, int line, const char *name); + +#define trace2_cmd_name(v) trace2_cmd_name_fl(__FILE__, __LINE__, (v)) + +/* + * Emit a 'cmd_mode' event to further describe the command being run. + * For example, "checkout" can checkout a single file or can checkout a + * different branch. This gives post-processors a simple field to compare + * equivalent commands without having to parse the argv. + */ +void trace2_cmd_mode_fl(const char *file, int line, const char *mode); + +#define trace2_cmd_mode(sv) trace2_cmd_mode_fl(__FILE__, __LINE__, (sv)) + +/* + * Emits an "alias" message containing the alias used and the argument + * expansion. + */ +void trace2_cmd_alias_fl(const char *file, int line, const char *alias, + const char **argv); + +#define trace2_cmd_alias(alias, argv) \ + trace2_cmd_alias_fl(__FILE__, __LINE__, (alias), (argv)) + +/* + * Emit one or more 'def_param' events for "important" configuration + * settings. + * + * Use the TR2_SYSENV_CFG_PARAM setting to register a comma-separated + * list of patterns configured important. For example: + * git config --system trace2.configParams 'core.*,remote.*.url' + * or: + * GIT_TRACE2_CONFIG_PARAMS=core.*,remote.*.url" + * + * Note: this routine does a read-only iteration on the config data + * (using read_early_config()), so it must not be called until enough + * of the process environment has been established. This includes the + * location of the git and worktree directories, expansion of any "-c" + * and "-C" command line options, and etc. + */ +void trace2_cmd_list_config_fl(const char *file, int line); + +#define trace2_cmd_list_config() trace2_cmd_list_config_fl(__FILE__, __LINE__) + +/* + * Emit one or more 'def_param' events for "important" environment variables. + * + * Use the TR2_SYSENV_ENV_VARS setting to register a comma-separated list of + * environment variables considered important. For example: + * git config --system trace2.envVars 'GIT_HTTP_USER_AGENT,GIT_CONFIG' + * or: + * GIT_TRACE2_ENV_VARS="GIT_HTTP_USER_AGENT,GIT_CONFIG" + */ +void trace2_cmd_list_env_vars_fl(const char *file, int line); + +#define trace2_cmd_list_env_vars() trace2_cmd_list_env_vars_fl(__FILE__, __LINE__) + +/* + * Emit a "def_param" event for the given config key/value pair IF + * we consider the key to be "important". + * + * Use this for new/updated config settings created/updated after + * trace2_cmd_list_config() is called. + */ +void trace2_cmd_set_config_fl(const char *file, int line, const char *key, + const char *value); + +#define trace2_cmd_set_config(k, v) \ + trace2_cmd_set_config_fl(__FILE__, __LINE__, (k), (v)) + +/** + * Emits a "child_start" message containing the "child-id", + * "child-argv", and "child-classification". + * + * Before calling optionally set "cmd->trace2_child_class" to a string + * describing the type of the child process. For example, "editor" or + * "pager". + * + * This function assigns a unique "child-id" to `cmd->trace2_child_id`. + * This field is used later during the "child_exit" message to associate + * it with the "child_start" message. + * + * This function should be called before spawning the child process. + */ +void trace2_child_start_fl(const char *file, int line, + struct child_process *cmd); + +#define trace2_child_start(cmd) trace2_child_start_fl(__FILE__, __LINE__, (cmd)) + +/** + * Emits a "child_exit" message containing the "child-id", + * the child's elapsed time and exit-code. + * + * The reported elapsed time includes the process creation overhead and + * time spend waiting for it to exit, so it may be slightly longer than + * the time reported by the child itself. + * + * This function should be called after reaping the child process. + */ +void trace2_child_exit_fl(const char *file, int line, struct child_process *cmd, + int child_exit_code); + +#define trace2_child_exit(cmd, code) \ + trace2_child_exit_fl(__FILE__, __LINE__, (cmd), (code)) + +/** + * Emit an 'exec' event prior to calling one of exec(), execv(), + * execvp(), and etc. On Unix-derived systems, this will be the + * last event emitted for the current process, unless the exec + * fails. On Windows, exec() behaves like 'child_start' and a + * waitpid(), so additional events may be emitted. + * + * Returns a unique "exec-id". This value is used later + * if the exec() fails and a "exec-result" message is necessary. + */ +int trace2_exec_fl(const char *file, int line, const char *exe, + const char **argv); + +#define trace2_exec(exe, argv) trace2_exec_fl(__FILE__, __LINE__, (exe), (argv)) + +/** + * Emit an 'exec_result' when possible. On Unix-derived systems, + * this should be called after exec() returns (which only happens + * when there is an error starting the new process). On Windows, + * this should be called after the waitpid(). + * + * The "exec_id" should be the value returned from trace2_exec(). + */ +void trace2_exec_result_fl(const char *file, int line, int exec_id, int code); + +#define trace2_exec_result(id, code) \ + trace2_exec_result_fl(__FILE__, __LINE__, (id), (code)) + +/* + * Emit a 'thread_start' event. This must be called from inside the + * thread-proc to set up the trace2 TLS data for the thread. + * + * Thread names should be descriptive, like "preload_index". + * Thread names will be decorated with an instance number automatically. + */ +void trace2_thread_start_fl(const char *file, int line, + const char *thread_name); + +#define trace2_thread_start(thread_name) \ + trace2_thread_start_fl(__FILE__, __LINE__, (thread_name)) + +/* + * Emit a 'thread_exit' event. This must be called from inside the + * thread-proc to report thread-specific data and cleanup TLS data + * for the thread. + */ +void trace2_thread_exit_fl(const char *file, int line); + +#define trace2_thread_exit() trace2_thread_exit_fl(__FILE__, __LINE__) + +/* + * Emits a "def_param" message containing a key/value pair. + * + * This message is intended to report some global aspect of the current + * command, such as a configuration setting or command line switch that + * significantly affects program performance or behavior, such as + * `core.abbrev`, `status.showUntrackedFiles`, or `--no-ahead-behind`. + */ +void trace2_def_param_fl(const char *file, int line, const char *param, + const char *value); + +#define trace2_def_param(param, value) \ + trace2_def_param_fl(__FILE__, __LINE__, (param), (value)) + +/* + * Tell trace2 about a newly instantiated repo object and assign + * a trace2-repo-id to be used in subsequent activity events. + * + * Emits a 'worktree' event for this repo instance. + * + * Region and data messages may refer to this repo-id. + * + * The main/top-level repository will have repo-id value 1 (aka "r1"). + * + * The repo-id field is in anticipation of future in-proc submodule + * repositories. + */ +void trace2_def_repo_fl(const char *file, int line, struct repository *repo); + +#define trace2_def_repo(repo) trace2_def_repo_fl(__FILE__, __LINE__, repo) + +/** + * Emit a 'region_enter' event for <category>.<label> with optional + * repo-id and printf message. + * + * This function pushes a new region nesting stack level on the current + * thread and starts a clock for the new stack frame. + * + * The `category` field is an arbitrary category name used to classify + * regions by feature area, such as "status" or "index". At this time + * it is only just printed along with the rest of the message. It may + * be used in the future to filter messages. + * + * The `label` field is an arbitrary label used to describe the activity + * being started, such as "read_recursive" or "do_read_index". + * + * The `repo` field, if set, will be used to get the "repo-id", so that + * recursive oerations can be attributed to the correct repository. + */ +void trace2_region_enter_fl(const char *file, int line, const char *category, + const char *label, const struct repository *repo, ...); + +#define trace2_region_enter(category, label, repo) \ + trace2_region_enter_fl(__FILE__, __LINE__, (category), (label), (repo)) + +void trace2_region_enter_printf_va_fl(const char *file, int line, + const char *category, const char *label, + const struct repository *repo, + const char *fmt, va_list ap); + +#define trace2_region_enter_printf_va(category, label, repo, fmt, ap) \ + trace2_region_enter_printf_va_fl(__FILE__, __LINE__, (category), \ + (label), (repo), (fmt), (ap)) + +void trace2_region_enter_printf_fl(const char *file, int line, + const char *category, const char *label, + const struct repository *repo, + const char *fmt, ...); + +#ifdef HAVE_VARIADIC_MACROS +#define trace2_region_enter_printf(category, label, repo, ...) \ + trace2_region_enter_printf_fl(__FILE__, __LINE__, (category), (label), \ + (repo), __VA_ARGS__) +#else +/* clang-format off */ +__attribute__((format (region_enter_printf, 4, 5))) +void trace2_region_enter_printf(const char *category, const char *label, + const struct repository *repo, const char *fmt, + ...); +/* clang-format on */ +#endif + +/** + * Emit a 'region_leave' event for <category>.<label> with optional + * repo-id and printf message. + * + * Leave current nesting level and report the elapsed time spent + * in this nesting level. + * + * The `category`, `label`, and `repo` fields are the same as + * trace2_region_enter_fl. The `category` and `label` do not + * need to match the corresponding "region_enter" message, + * but it makes the data stream easier to understand. + */ +void trace2_region_leave_fl(const char *file, int line, const char *category, + const char *label, const struct repository *repo, ...); + +#define trace2_region_leave(category, label, repo) \ + trace2_region_leave_fl(__FILE__, __LINE__, (category), (label), (repo)) + +void trace2_region_leave_printf_va_fl(const char *file, int line, + const char *category, const char *label, + const struct repository *repo, + const char *fmt, va_list ap); + +#define trace2_region_leave_printf_va(category, label, repo, fmt, ap) \ + trace2_region_leave_printf_va_fl(__FILE__, __LINE__, (category), \ + (label), (repo), (fmt), (ap)) + +void trace2_region_leave_printf_fl(const char *file, int line, + const char *category, const char *label, + const struct repository *repo, + const char *fmt, ...); + +#ifdef HAVE_VARIADIC_MACROS +#define trace2_region_leave_printf(category, label, repo, ...) \ + trace2_region_leave_printf_fl(__FILE__, __LINE__, (category), (label), \ + (repo), __VA_ARGS__) +#else +/* clang-format off */ +__attribute__((format (region_leave_printf, 4, 5))) +void trace2_region_leave_printf(const char *category, const char *label, + const struct repository *repo, const char *fmt, + ...); +/* clang-format on */ +#endif + +/** + * Emit a key-value pair 'data' event of the form <category>.<key> = <value>. + * This event implicitly contains information about thread, nesting region, + * and optional repo-id. + * This could be used to print the number of files in a directory during + * a multi-threaded recursive tree walk. + * + * On event-based TRACE2 targets, this generates a 'data' event suitable + * for post-processing. On printf-based TRACE2 targets, this is converted + * into a fixed-format printf message. + */ +void trace2_data_string_fl(const char *file, int line, const char *category, + const struct repository *repo, const char *key, + const char *value); + +#define trace2_data_string(category, repo, key, value) \ + trace2_data_string_fl(__FILE__, __LINE__, (category), (repo), (key), \ + (value)) + +void trace2_data_intmax_fl(const char *file, int line, const char *category, + const struct repository *repo, const char *key, + intmax_t value); + +#define trace2_data_intmax(category, repo, key, value) \ + trace2_data_intmax_fl(__FILE__, __LINE__, (category), (repo), (key), \ + (value)) + +void trace2_data_json_fl(const char *file, int line, const char *category, + const struct repository *repo, const char *key, + const struct json_writer *jw); + +#define trace2_data_json(category, repo, key, value) \ + trace2_data_json_fl(__FILE__, __LINE__, (category), (repo), (key), \ + (value)) + +/* + * Emit a 'printf' event. + * + * Write an arbitrary formatted message to the TRACE2 targets. These + * text messages should be considered as human-readable strings without + * any formatting guidelines. Post-processors may choose to ignore + * them. + */ +void trace2_printf_va_fl(const char *file, int line, const char *fmt, + va_list ap); + +#define trace2_printf_va(fmt, ap) \ + trace2_printf_va_fl(__FILE__, __LINE__, (fmt), (ap)) + +void trace2_printf_fl(const char *file, int line, const char *fmt, ...); + +#ifdef HAVE_VARIADIC_MACROS +#define trace2_printf(...) trace2_printf_fl(__FILE__, __LINE__, __VA_ARGS__) +#else +/* clang-format off */ +__attribute__((format (printf, 1, 2))) +void trace2_printf(const char *fmt, ...); +/* clang-format on */ +#endif + +/* + * Optional platform-specific code to dump information about the + * current and any parent process(es). This is intended to allow + * post-processors to know who spawned this git instance and anything + * else that the platform may be able to tell us about the current process. + */ + +enum trace2_process_info_reason { + TRACE2_PROCESS_INFO_STARTUP, + TRACE2_PROCESS_INFO_EXIT, +}; + +#if defined(GIT_WINDOWS_NATIVE) +void trace2_collect_process_info(enum trace2_process_info_reason reason); +#else +#define trace2_collect_process_info(reason) \ + do { \ + } while (0) +#endif + +const char *trace2_session_id(void); + +#endif /* TRACE2_H */ |