Can I please get a review for this test-only change which proposes to improve the test run duration of `java/net/vthread/HttpALot.java` test, on Linux? This relates to https://bugs.openjdk.org/browse/JDK-8294610
Experiments have shown that on Linux, due to delayed TCP ACKs from the client (for some previous sent data/packet), the server sent response waits for the ACKs before sending the response data (in a TCP packet). Each delayed ACK is 40 milli seconds and given the number of requests this test (intentionally) issues, the delay accumulates causing the test to take longer duration. With the change in this PR, the test completes in around 6 to 8 seconds on a Linux system as compared to 60 odd seconds previously on the same setup. This change hasn't shown any negative impact on macos (which continues to run this test in around 5 to 6 seconds like previously). I will trigger some runs in our CI setup to make sure this works as expected in all other OS too. As noted in the linked JBS issue, additional experiments to see if anything can be improved in the JDK network layer will be carried out separately, outside the context of this test. ------------- Commit messages: - 8294610: java/net/vthread/HttpALot.java is slow on Linux Changes: https://git.openjdk.org/jdk/pull/10504/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10504&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8294610 Stats: 7 lines in 1 file changed: 7 ins; 0 del; 0 mod Patch: https://git.openjdk.org/jdk/pull/10504.diff Fetch: git fetch https://git.openjdk.org/jdk pull/10504/head:pull/10504 PR: https://git.openjdk.org/jdk/pull/10504
