From a4324a996f34902579338033110d27575a654c8e Mon Sep 17 00:00:00 2001 From: Dave Barach Date: Tue, 19 Feb 2019 17:05:30 -0500 Subject: calculate per-thread time offset The main thread squirrels away vlib_time_now (&vlib_global_main), worker threads use it to calculate an offset in f64 seconds from their own vlib_time_now(vm) value. We use that offset until the next barrier sync. Thanks to Damjan for the suggestion. Change-Id: If56cdfe68e5ad8ac3b0d0fc885dc3ba556cd1215 Signed-off-by: Dave Barach --- src/vlib/threads.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) (limited to 'src/vlib/threads.c') diff --git a/src/vlib/threads.c b/src/vlib/threads.c index cdb4eb082b5..4368a74ac9f 100644 --- a/src/vlib/threads.c +++ b/src/vlib/threads.c @@ -1510,6 +1510,14 @@ vlib_worker_thread_barrier_release (vlib_main_t * vm) deadline = now + BARRIER_SYNC_TIMEOUT; + /* + * Note when we let go of the barrier. + * Workers can use this to derive a reasonably accurate + * time offset. See vlib_time_now(...) + */ + vm->time_last_barrier_release = vlib_time_now (vm); + CLIB_MEMORY_STORE_BARRIER (); + *vlib_worker_threads->wait_at_barrier = 0; while (*vlib_worker_threads->workers_at_barrier > 0) @@ -1808,6 +1816,45 @@ threads_init (vlib_main_t * vm) VLIB_INIT_FUNCTION (threads_init); + +static clib_error_t * +show_clock_command_fn (vlib_main_t * vm, + unformat_input_t * input, vlib_cli_command_t * cmd) +{ + int i; + f64 now; + + now = vlib_time_now (vm); + + vlib_cli_output (vm, "Time now %.9f", now); + + if (vec_len (vlib_mains) == 1) + return 0; + + vlib_cli_output (vm, "Time last barrier release %.9f", + vm->time_last_barrier_release); + + for (i = 1; i < vec_len (vlib_mains); i++) + { + if (vlib_mains[i] == 0) + continue; + vlib_cli_output (vm, "Thread %d offset %.9f error %.9f", i, + vlib_mains[i]->time_offset, + vm->time_last_barrier_release - + vlib_mains[i]->time_last_barrier_release); + } + return 0; +} + +/* *INDENT-OFF* */ +VLIB_CLI_COMMAND (f_command, static) = +{ + .path = "show clock", + .short_help = "show clock", + .function = show_clock_command_fn, +}; +/* *INDENT-ON* */ + /* * fd.io coding-style-patch-verification: ON * -- cgit 1.2.3-korg