Hi,
Please find below a test-only change to fix some intermittent failures observed
with the httpclient/websocket tests:
these tests intermittently and randomly fail with ENOMEM ("No buffer space
available").
Some machines in our CI seem to allow a higher level of concurrency while being
(maybe) configured with lower system resources (such as available buffer space
for the TCP stack).
Some of the httpclient/websocket tests attempt to fill the sockets buffers in
order to assert some conditions when the buffers are full and writing is
paused. When the test process terminates, this leaves behind TCP sockets in the
TIME_WAIT state that still hold system buffer resources in case retransmission
is needed. When several such tests are run this ends up causing random "No
buffer space available" errors on other tests (including these tests
themselves) running concurrently or shortly after on the same machine.
This change implements a few tricks to alleviate the situation:
- configure the tests with smaller send buffers on the client side and receive
buffers on the server side, in order to limit how much buffer space is consumed
by the test.
- when the not-reading server is closed, and before the accepted socket is
closed, read all available data off the socket buffer in order to free up the
buffer space that the test has consumed before closing the socket.
- in some tests that create a large number of HttpClients, limit the number of
clients created in shared client mode, and add a call to System.gc() and a
small pause to give time for gc to collect the old clients which are no longer
referenced.
With these changes, I have run the HttpClient tests 200 times on the
problematic machines without observing any failures (where previously there was
at least a couple of failures per 50 runs). I also ran tier1 once, and tier2
twice and the results came clean.
I am therefore claiming success (even if it might prove temporary ;-) )
If these failures come back to haunt the CI again after this fix, a further
remediation policy could be to put the httpclient/websocket directory in
exclusive test execution mode (in TEST.root) - this seems to work too - but
cleaning up garbage in the tests themselves seems preferable.
-------------
Commit messages:
- 8268714: [macos-aarch64] 7 java/net/httpclient/websocket tests failed
Changes: https://git.openjdk.java.net/jdk17/pull/79/files
Webrev: https://webrevs.openjdk.java.net/?repo=jdk17&pr=79&range=00
Issue: https://bugs.openjdk.java.net/browse/JDK-8268714
Stats: 93 lines in 12 files changed: 86 ins; 0 del; 7 mod
Patch: https://git.openjdk.java.net/jdk17/pull/79.diff
Fetch: git fetch https://git.openjdk.java.net/jdk17 pull/79/head:pull/79
PR: https://git.openjdk.java.net/jdk17/pull/79
