e8effd4556
The API addition `uv_metrics_idle_time()` is a thread safe call that allows the user to retrieve the amount of time the event loop has spent in the kernel's event provider (i.e. poll). It was done this way to allow retrieving this value without needing to interrupt the execution of the event loop. This option can be enabled by passing `UV_METRICS_IDLE_TIME` to `uv_loop_configure()`. One important aspect of this change is, when enabled, to always first call the event provider with a `timeout == 0`. This allows libuv to know whether any events were waiting in the event queue when the event provider was called. The importance of this is because libuv is tracking the amount of "idle time", not "poll time". Thus the provider entry time is not recorded when `timeout == 0` (the event provider never idles in this case). While this does add a small amount of overhead, when enabled, but the overhead decreases when the event loop has a heavier load. This is because poll events will be waiting when the event provider is called. Thus never actually recording the provider entry time. Checking if `uv_loop_t` is configured with `UV_METRICS_IDLE_TIME` always happens in `uv__metrics_set_provider_entry_time()` and `uv__metrics_update_idle_time()`. Making the conditional logic wrapping each call simpler and allows for instrumentation to always hook into those two function calls. Rather than placing the fields directly on `uv__loop_internal_fields_t` add the struct `uv__loop_metrics_t` as a location for future metrics API additions. Tests and additional documentation has been included. PR-URL: https://github.com/libuv/libuv/pull/2725 Reviewed-By: Fedor Indutny <fedor.indutny@gmail.com> Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com> Reviewed-By: Jameson Nash <vtjnash@gmail.com>
115 lines
2.6 KiB
C
115 lines
2.6 KiB
C
#include "uv.h"
|
|
#include "task.h"
|
|
#include <string.h> /* memset */
|
|
|
|
#define NS_MS 1000000
|
|
|
|
|
|
static void timer_spin_cb(uv_timer_t* handle) {
|
|
uint64_t t;
|
|
|
|
(*(int*) handle->data)++;
|
|
t = uv_hrtime();
|
|
/* Spin for 500 ms to spin loop time out of the delta check. */
|
|
while (uv_hrtime() - t < 600 * NS_MS) { }
|
|
}
|
|
|
|
|
|
TEST_IMPL(metrics_idle_time) {
|
|
const uint64_t timeout = 1000;
|
|
uv_timer_t timer;
|
|
uint64_t idle_time;
|
|
int cntr;
|
|
|
|
cntr = 0;
|
|
timer.data = &cntr;
|
|
|
|
ASSERT_EQ(0, uv_loop_configure(uv_default_loop(), UV_METRICS_IDLE_TIME));
|
|
ASSERT_EQ(0, uv_timer_init(uv_default_loop(), &timer));
|
|
ASSERT_EQ(0, uv_timer_start(&timer, timer_spin_cb, timeout, 0));
|
|
|
|
ASSERT_EQ(0, uv_run(uv_default_loop(), UV_RUN_DEFAULT));
|
|
ASSERT_GT(cntr, 0);
|
|
|
|
idle_time = uv_metrics_idle_time(uv_default_loop());
|
|
|
|
/* Permissive check that the idle time matches within the timeout ±500 ms. */
|
|
ASSERT((idle_time <= (timeout + 500) * NS_MS) &&
|
|
(idle_time >= (timeout - 500) * NS_MS));
|
|
|
|
MAKE_VALGRIND_HAPPY();
|
|
return 0;
|
|
}
|
|
|
|
|
|
static void metrics_routine_cb(void* arg) {
|
|
const uint64_t timeout = 1000;
|
|
uv_loop_t loop;
|
|
uv_timer_t timer;
|
|
uint64_t idle_time;
|
|
int cntr;
|
|
|
|
cntr = 0;
|
|
timer.data = &cntr;
|
|
|
|
ASSERT_EQ(0, uv_loop_init(&loop));
|
|
ASSERT_EQ(0, uv_loop_configure(&loop, UV_METRICS_IDLE_TIME));
|
|
ASSERT_EQ(0, uv_timer_init(&loop, &timer));
|
|
ASSERT_EQ(0, uv_timer_start(&timer, timer_spin_cb, timeout, 0));
|
|
|
|
ASSERT_EQ(0, uv_run(&loop, UV_RUN_DEFAULT));
|
|
ASSERT_GT(cntr, 0);
|
|
|
|
idle_time = uv_metrics_idle_time(&loop);
|
|
|
|
/* Only checking that idle time is greater than the lower bound since there
|
|
* may have been thread contention, causing the event loop to be delayed in
|
|
* the idle phase longer than expected.
|
|
*/
|
|
ASSERT_GE(idle_time, (timeout - 500) * NS_MS);
|
|
|
|
close_loop(&loop);
|
|
ASSERT_EQ(0, uv_loop_close(&loop));
|
|
}
|
|
|
|
|
|
TEST_IMPL(metrics_idle_time_thread) {
|
|
uv_thread_t threads[5];
|
|
int i;
|
|
|
|
for (i = 0; i < 5; i++) {
|
|
ASSERT_EQ(0, uv_thread_create(&threads[i], metrics_routine_cb, NULL));
|
|
}
|
|
|
|
for (i = 0; i < 5; i++) {
|
|
uv_thread_join(&threads[i]);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
static void timer_noop_cb(uv_timer_t* handle) {
|
|
(*(int*) handle->data)++;
|
|
}
|
|
|
|
|
|
TEST_IMPL(metrics_idle_time_zero) {
|
|
uv_timer_t timer;
|
|
int cntr;
|
|
|
|
cntr = 0;
|
|
timer.data = &cntr;
|
|
ASSERT_EQ(0, uv_loop_configure(uv_default_loop(), UV_METRICS_IDLE_TIME));
|
|
ASSERT_EQ(0, uv_timer_init(uv_default_loop(), &timer));
|
|
ASSERT_EQ(0, uv_timer_start(&timer, timer_noop_cb, 0, 0));
|
|
|
|
ASSERT_EQ(0, uv_run(uv_default_loop(), UV_RUN_DEFAULT));
|
|
|
|
ASSERT_GT(cntr, 0);
|
|
ASSERT_EQ(0, uv_metrics_idle_time(uv_default_loop()));
|
|
|
|
MAKE_VALGRIND_HAPPY();
|
|
return 0;
|
|
}
|