git/trace2/tr2_tls.h
Jeff Hostetler ee4512ed48 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>
2019-02-22 15:27:59 -08:00

97 lines
2.2 KiB
C

#ifndef TR2_TLS_H
#define TR2_TLS_H
#include "strbuf.h"
/*
* Arbitry limit for thread names for column alignment.
*/
#define TR2_MAX_THREAD_NAME (24)
struct tr2tls_thread_ctx {
struct strbuf thread_name;
uint64_t *array_us_start;
int alloc;
int nr_open_regions; /* plays role of "nr" in ALLOC_GROW */
int thread_id;
};
/*
* Create TLS data for the current thread. This gives us a place to
* put per-thread data, such as thread start time, function nesting
* and a per-thread label for our messages.
*
* We assume the first thread is "main". Other threads are given
* non-zero thread-ids to help distinguish messages from concurrent
* threads.
*
* Truncate the thread name if necessary to help with column alignment
* in printf-style messages.
*
* In this and all following functions the term "self" refers to the
* current thread.
*/
struct tr2tls_thread_ctx *tr2tls_create_self(const char *thread_name);
/*
* Get our TLS data.
*/
struct tr2tls_thread_ctx *tr2tls_get_self(void);
/*
* return true if the current thread is the main thread.
*/
int tr2tls_is_main_thread(void);
/*
* Free our TLS data.
*/
void tr2tls_unset_self(void);
/*
* Begin a new nested region and remember the start time.
*/
void tr2tls_push_self(uint64_t us_now);
/*
* End the innermost nested region.
*/
void tr2tls_pop_self(void);
/*
* Pop any extra (above the first) open regions on the current
* thread and discard. During a thread-exit, we should only
* have region[0] that was pushed in trace2_thread_start() if
* the thread exits normally.
*/
void tr2tls_pop_unwind_self(void);
/*
* Compute the elapsed time since the innermost region in the
* current thread started and the given time (usually now).
*/
uint64_t tr2tls_region_elasped_self(uint64_t us);
/*
* Compute the elapsed time since the main thread started
* and the given time (usually now). This is assumed to
* be the absolute run time of the process.
*/
uint64_t tr2tls_absolute_elapsed(uint64_t us);
/*
* Initialize the tr2 TLS system.
*/
void tr2tls_init(void);
/*
* Free all tr2 TLS resources.
*/
void tr2tls_release(void);
/*
* Protected increment of an integer.
*/
int tr2tls_locked_increment(int *p);
#endif /* TR2_TLS_H */