On Fri, 18 Oct 2024 22:36:33 GMT, Sergey Bylokhov <s...@openjdk.org> wrote:
>> This test follows the same pattern that I used in >> https://github.com/openjdk/jdk/pull/21474: >> >> https://github.com/openjdk/jdk/pull/21474/files#diff-2a8cee50408407d7e24de4cb85f0921cfc5db7c215d3b29cf101a4050323e9a9R92 > >> To ensure all the events in the queue are handled, I added >> `robot.waitForIdle()`. > > This will flush events which were posted after the windows gained focus, but > before the patch the test flushed all events (including event to show the > window which might be asynchronous). My point is that this operation might be > longer that 1 second(one of the reason we have all that deleyas). So we > should waitForIdle first, then wait via delay or other sync_ops. This will flush all the pending events in the queue, which includes events that were posted before the `windowGainedFocus` latch is released as well as events are posted afterwards. There's no difference whether I place `waitForIdle` before or after. If I place `robot.waitForIdle` before `windowGainedFocus.await`, then `await` immediately returns, that is the delay added by `await` is zero. If I place `robot.waitForIdle` after `windowGainedFocus.await`, the main thread stops until the window gained focus event is delivered, after which `robot.waitForIdle` flushes the remaining events in the queue. In both cases, there's a slight possibility `windowGainedFocus` is never triggered if the window didn't get focus for whatever reason… On my Windows 11 laptop, the average time (over 20 runs of the `bug4323121` test) * for `windowGainedFocus.await`: 12 ms * for `robot.waitForIdle`: 36 ms * or cumulatively: 48 ms If I change the order of calls, * for `robot.waitForIdle`: 51 ms * for `windowGainedFocus.await`: 0 ms * or cumulatively: 51 ms Both versions align well — `robot.waitForIdle` takes about 50 ms. (The version where `waitForIdle` follows `await` is slightly quicker because `await` does nothing at all whereas `waitForIdle` posts events from its own copy of the queue for handling. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/21475#discussion_r1809317633
