git/trace2/tr2_ctr.c
Junio C Hamano 52d9dc20e1 Merge branch 'bb/use-trace2-counters-for-fsync-stats'
Instead of inventing a custom counter variables for debugging,
use existing trace2 facility in the fsync customization codepath.

* bb/use-trace2-counters-for-fsync-stats:
  wrapper: use trace2 counters to collect fsync stats
2023-08-02 09:37:23 -07:00

116 lines
3 KiB
C

#include "git-compat-util.h"
#include "thread-utils.h"
#include "trace2/tr2_tgt.h"
#include "trace2/tr2_tls.h"
#include "trace2/tr2_ctr.h"
/*
* A global counter block to aggregrate values from the partial sums
* from each thread.
*/
static struct tr2_counter_block final_counter_block; /* access under tr2tls_mutex */
/*
* Define metadata for each global counter.
*
* This array must match the "enum trace2_counter_id" and the values
* in "struct tr2_counter_block.counter[*]".
*/
static struct tr2_counter_metadata tr2_counter_metadata[TRACE2_NUMBER_OF_COUNTERS] = {
[TRACE2_COUNTER_ID_TEST1] = {
.category = "test",
.name = "test1",
.want_per_thread_events = 0,
},
[TRACE2_COUNTER_ID_TEST2] = {
.category = "test",
.name = "test2",
.want_per_thread_events = 1,
},
[TRACE2_COUNTER_ID_PACKED_REFS_JUMPS] = {
.category = "packed-refs",
.name = "jumps_made",
.want_per_thread_events = 0,
},
[TRACE2_COUNTER_ID_FSYNC_WRITEOUT_ONLY] = {
.category = "fsync",
.name = "writeout-only",
.want_per_thread_events = 0,
},
[TRACE2_COUNTER_ID_FSYNC_HARDWARE_FLUSH] = {
.category = "fsync",
.name = "hardware-flush",
.want_per_thread_events = 0,
},
/* Add additional metadata before here. */
};
void tr2_counter_increment(enum trace2_counter_id cid, uint64_t value)
{
struct tr2tls_thread_ctx *ctx = tr2tls_get_self();
struct tr2_counter *c = &ctx->counter_block.counter[cid];
c->value += value;
ctx->used_any_counter = 1;
if (tr2_counter_metadata[cid].want_per_thread_events)
ctx->used_any_per_thread_counter = 1;
}
void tr2_update_final_counters(void)
{
struct tr2tls_thread_ctx *ctx = tr2tls_get_self();
enum trace2_counter_id cid;
if (!ctx->used_any_counter)
return;
/*
* Access `final_counter_block` requires holding `tr2tls_mutex`.
* We assume that our caller is holding the lock.
*/
for (cid = 0; cid < TRACE2_NUMBER_OF_COUNTERS; cid++) {
struct tr2_counter *c_final = &final_counter_block.counter[cid];
const struct tr2_counter *c = &ctx->counter_block.counter[cid];
c_final->value += c->value;
}
}
void tr2_emit_per_thread_counters(tr2_tgt_evt_counter_t *fn_apply)
{
struct tr2tls_thread_ctx *ctx = tr2tls_get_self();
enum trace2_counter_id cid;
if (!ctx->used_any_per_thread_counter)
return;
/*
* For each counter, if the counter wants per-thread events
* and this thread used it (the value is non-zero), emit it.
*/
for (cid = 0; cid < TRACE2_NUMBER_OF_COUNTERS; cid++)
if (tr2_counter_metadata[cid].want_per_thread_events &&
ctx->counter_block.counter[cid].value)
fn_apply(&tr2_counter_metadata[cid],
&ctx->counter_block.counter[cid],
0);
}
void tr2_emit_final_counters(tr2_tgt_evt_counter_t *fn_apply)
{
enum trace2_counter_id cid;
/*
* Access `final_counter_block` requires holding `tr2tls_mutex`.
* We assume that our caller is holding the lock.
*/
for (cid = 0; cid < TRACE2_NUMBER_OF_COUNTERS; cid++)
if (final_counter_block.counter[cid].value)
fn_apply(&tr2_counter_metadata[cid],
&final_counter_block.counter[cid],
1);
}