On Mon, 9 Sep 2024 22:29:23 GMT, Aleksei Efimov <aefi...@openjdk.org> wrote:
>> This PR proposes the following changes to address wrong timeout computations >> in the `com.sun.jndi.dns.DnsClient`: >> - The `DnsClient` has been updated to use a monotonic high-resolution (nano) >> clock. The existing `Timeout` test has also been updated to use the nano >> clock to measure observed timeout value. >> >> - The left timeout computation has been fixed to decrease the timeout value >> during each retry attempt. A new test, `TimeoutWithEmptyDatagrams`, has been >> added to test it. >> >> - The `DnsClient.blockingReceive` has been updated: >> - to detect if any data is received >> - to avoid contention with `Selector.close()` that could be called by a >> cleaner thread >> >> - The expected timeout calculation in the `Timeout` test has been updated to >> take into account the minimum retry timeout (50ms). Additionally, the max >> allowed difference between the observed timeout and the expected one has >> been increased from 50% to 67%. Taking into account 50 ms retry timeout >> decrease the maximum allowed difference is effectively set to 61%. This >> change is expected to improve the stability of the `Timeout` test which has >> been seen to fail >> [intermittentlly](https://bugs.openjdk.org/browse/JDK-8220213). If no >> objections, I'm planning to close >> [JDK-8220213](https://bugs.openjdk.org/browse/JDK-8220213) as duplicate of >> this one. >> >> JNDI/DNS jtreg tests has been executed multiple times (500+) to check if the >> new and the modified tests are stable. No failures been observed (so far?). > > Aleksei Efimov has updated the pull request incrementally with one additional > commit since the last revision: > > Measure time the caller spent waiting. Simplify timeoutLeft computation test/jdk/com/sun/jndi/dns/ConfigTests/Timeout.java line 112: > 110: // Check that elapsed time is as long as expected, and > 111: // not more than 67% greater. Given the min DNS timeout > 112: // correction above the threshold value is equal to 61%. this is a bit arcane, why not have a simple measure that elapsed time shouldn't be more than twice the expected timeout ... this is not that different to the multipliedBy(2) and multipliedBy(3) -- elaspedTime.compareTo(expectedTime.multipliedBy(2) <= 0 Additionally based on the internal minimum timeout allowance of 50 secs and this upper bound calculation, it would suggest that an @implNote might be useful, or required, to alert developers to potential timeout variability, and not to rely on timeout to be absolutely (real time) precise ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/20892#discussion_r1751636105
