trace2: create new combined trace facility

Create a new unified tracing facility for git.  The eventual intent is to
replace the current trace_printf* and trace_performance* routines with a
unified set of git_trace2* routines.

In addition to the usual printf-style API, trace2 provides higer-level
event verbs with fixed-fields allowing structured data to be written.
This makes post-processing and analysis easier for external tools.

Trace2 defines 3 output targets.  These are set using the environment
variables "GIT_TR2", "GIT_TR2_PERF", and "GIT_TR2_EVENT".  These may be
set to "1" or to an absolute pathname (just like the current GIT_TRACE).

* GIT_TR2 is intended to be a replacement for GIT_TRACE and logs command
  summary data.

* GIT_TR2_PERF is intended as a replacement for GIT_TRACE_PERFORMANCE.
  It extends the output with columns for the command process, thread,
  repo, absolute and relative elapsed times.  It reports events for
  child process start/stop, thread start/stop, and per-thread function
  nesting.

* GIT_TR2_EVENT is a new structured format. It writes event data as a
  series of JSON records.

Calls to trace2 functions log to any of the 3 output targets enabled
without the need to call different trace_printf* or trace_performance*
routines.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jeff Hostetler
2019-02-22 14:25:01 -08:00
committed by Junio C Hamano
parent e544221d97
commit ee4512ed48
39 changed files with 3806 additions and 18 deletions

View File

@ -10,6 +10,12 @@ struct child_process {
struct argv_array args;
struct argv_array env_array;
pid_t pid;
int trace2_child_id;
uint64_t trace2_child_us_start;
const char *trace2_child_class;
const char *trace2_hook_name;
/*
* Using .in, .out, .err:
* - Specify 0 for no redirections (child inherits stdin, stdout,
@ -73,12 +79,14 @@ extern int run_hook_ve(const char *const *env, const char *name, va_list args);
#define RUN_USING_SHELL 16
#define RUN_CLEAN_ON_EXIT 32
int run_command_v_opt(const char **argv, int opt);
int run_command_v_opt_tr2(const char **argv, int opt, const char *tr2_class);
/*
* env (the environment) is to be formatted like environ: "VAR=VALUE".
* To unset an environment variable use just "VAR".
*/
int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env);
int run_command_v_opt_cd_env_tr2(const char **argv, int opt, const char *dir,
const char *const *env, const char *tr2_class);
/**
* Execute the given command, sending "in" to its stdin, and capturing its
@ -220,5 +228,8 @@ int run_processes_parallel(int n,
start_failure_fn,
task_finished_fn,
void *pp_cb);
int run_processes_parallel_tr2(int n, get_next_task_fn, start_failure_fn,
task_finished_fn, void *pp_cb,
const char *tr2_category, const char *tr2_label);
#endif