From 000a029e4a6a481f35b978dfe474c82d8da88e95 Mon Sep 17 00:00:00 2001 From: Dave Barach Date: Mon, 17 Feb 2020 17:07:12 -0500 Subject: vlib: calculate per-worker loops/second metric Use exponential smoothing. Each sample has a half-life of 1 second. reported_rate(t) = reported_rate(t-1) * K + rate(t)*(1-K) Sample every 20ms, i.e. 50 samples per second K = exp (-1.0/20.0); K = 0.95; Type: feature Signed-off-by: Dave Barach Change-Id: I9aea5dd5fecfaefffb78245316adb4bf62eb2bd4 --- src/vlib/main.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) (limited to 'src/vlib/main.c') diff --git a/src/vlib/main.c b/src/vlib/main.c index 94218d3d9d8..f723d106120 100644 --- a/src/vlib/main.c +++ b/src/vlib/main.c @@ -1683,6 +1683,7 @@ vlib_main_or_worker_loop (vlib_main_t * vm, int is_main) vlib_thread_main_t *tm = vlib_get_thread_main (); uword i; u64 cpu_time_now; + f64 now; vlib_frame_queue_main_t *fqm; u32 *last_node_runtime_indices = 0; u32 frame_queue_check_counter = 0; @@ -1926,6 +1927,33 @@ vlib_main_or_worker_loop (vlib_main_t * vm, int is_main) /* Record time stamp in case there are no enabled nodes and above calls do not update time stamp. */ cpu_time_now = clib_cpu_time_now (); + vm->loops_this_reporting_interval++; + now = clib_time_now_internal (&vm->clib_time, cpu_time_now); + /* Time to update loops_per_second? */ + if (PREDICT_FALSE (now >= vm->loop_interval_end)) + { + /* Next sample ends in 20ms */ + if (vm->loop_interval_start) + { + f64 this_loops_per_second; + + this_loops_per_second = + ((f64) vm->loops_this_reporting_interval) / (now - + vm->loop_interval_start); + + vm->loops_per_second = + vm->loops_per_second * vm->damping_constant + + (1.0 - vm->damping_constant) * this_loops_per_second; + if (vm->loops_per_second != 0.0) + vm->seconds_per_loop = 1.0 / vm->loops_per_second; + else + vm->seconds_per_loop = 0.0; + } + /* New interval starts now, and ends in 20ms */ + vm->loop_interval_start = now; + vm->loop_interval_end = now + 2e-4; + vm->loops_this_reporting_interval = 0; + } } } @@ -2122,6 +2150,16 @@ vlib_main (vlib_main_t * volatile vm, unformat_input_t * input) if ((error = vlib_call_all_config_functions (vm, input, 0 /* is_early */ ))) goto done; + /* + * Use exponential smoothing, with a half-life of 1 second + * reported_rate(t) = reported_rate(t-1) * K + rate(t)*(1-K) + * + * Sample every 20ms, aka 50 samples per second + * K = exp (-1.0/20.0); + * K = 0.95 + */ + vm->damping_constant = exp (-1.0 / 20.0); + /* Sort per-thread init functions before we start threads */ vlib_sort_init_exit_functions (&vm->worker_init_function_registrations); -- cgit 1.2.3-korg