diff options
Diffstat (limited to 'docs/src')
| -rw-r--r-- | docs/src/design.rst | 17 | ||||
| -rw-r--r-- | docs/src/static/loop_iteration.png | bin | 80528 -> 65186 bytes |
2 files changed, 9 insertions, 8 deletions
diff --git a/docs/src/design.rst b/docs/src/design.rst index 0f5580c7..5a20595c 100644 --- a/docs/src/design.rst +++ b/docs/src/design.rst @@ -60,16 +60,15 @@ stages of a loop iteration: :align: center -#. The loop concept of 'now' is updated. The event loop caches the current time at the start of - the event loop tick in order to reduce the number of time-related system calls. +#. The loop concept of 'now' is initially set. + +#. Due timers are run if the loop was run with ``UV_RUN_DEFAULT``. All active timers scheduled + for a time before the loop's concept of *now* get their callbacks called. #. If the loop is *alive* an iteration is started, otherwise the loop will exit immediately. So, when is a loop considered to be *alive*? If a loop has active and ref'd handles, active requests or closing handles it's considered to be *alive*. -#. Due timers are run. All active timers scheduled for a time before the loop's concept of *now* - get their callbacks called. - #. Pending callbacks are called. All I/O callbacks are called right after polling for I/O, for the most part. There are cases, however, in which calling such a callback is deferred for the next loop iteration. If the previous iteration deferred any I/O callback it will be run at this point. @@ -101,9 +100,11 @@ stages of a loop iteration: #. Close callbacks are called. If a handle was closed by calling :c:func:`uv_close` it will get the close callback called. -#. Special case in case the loop was run with ``UV_RUN_ONCE``, as it implies forward progress. - It's possible that no I/O callbacks were fired after blocking for I/O, but some time has passed - so there might be timers which are due, those timers get their callbacks called. +#. The loop concept of 'now' is updated. + +#. Due timers are run. Note that 'now' is not updated again until the next loop iteration. + So if a timer became due while other timers were being processed, it won't be run until + the following event loop iteration. #. Iteration ends. If the loop was run with ``UV_RUN_NOWAIT`` or ``UV_RUN_ONCE`` modes the iteration ends and :c:func:`uv_run` will return. If the loop was run with ``UV_RUN_DEFAULT`` diff --git a/docs/src/static/loop_iteration.png b/docs/src/static/loop_iteration.png Binary files differindex e769cf33..1545f84a 100644 --- a/docs/src/static/loop_iteration.png +++ b/docs/src/static/loop_iteration.png |
