I added a new test specifically to address this issue. Ran fine on osx without changes - long duration (failure) on Linux without the fix.
> On Apr 8, 2024, at 4:01 AM, Jaikiran Pai <jai.forums2...@gmail.com> wrote: > > Recently on AIX the same change was needed to address the test time outs in > the test/jdk/com/sun/net/httpserver/simpleserver/StressDirListings.java test > - https://github.com/openjdk/jdk/pull/17363 > > -Jaikiran > >> On 08/04/24 1:50 pm, Daniel Jeliński wrote: >> Hi Robert, >> If you are on Linux, see test/jdk/java/net/vthread/HttpALot.java. That >> test was recently modified to add -Dsun.net.httpserver.nodelay=true >> [1], because it took forever to complete on LInux machines. On other >> OSes the problem is not visible in existing tests. >> Cheers, >> Daniel >> >> [1] https://github.com/openjdk/jdk/pull/10504 >> >> sob., 6 kwi 2024 o 00:37 robert engels <reng...@ix.netcom.com> napisał(a): >>> Hi Daniel, >>> >>> I think I have a solution that would work. I will try to get a PR together. >>> Do you know if there is an existing test case the demonstrates the issue? - >>> if not, I will start with that. >>> >>> Robert >>> >>>> On Apr 4, 2024, at 9:44 AM, Daniel Jeliński <djelins...@gmail.com> wrote: >>> >>> Hi Robert, >>> Thanks for bringing this up! We are aware of the issue, it's tracked under >>> https://bugs.openjdk.org/browse/JDK-6968351. >>> >>> If you have an idea for a proper fix that doesn't add too much complexity, >>> please open a PR, and we'll be happy to help. >>> Cheers, >>> Daniel >>> >>> czw., 4 kwi 2024, 14:55 użytkownik Robert Engels <reng...@ix.netcom.com> >>> napisał: >>>> >>>> When doing some testing on github.com/robaho/httpserver - which is a fork >>>> of the jdk http server, I discovered a significant performance issue. >>>> >>>> When an http connection is in ‘keep-alive’ - the default for http 1.1 - >>>> the headers are “flushed” here >>>> https://github.com/openjdk/jdk21/blob/890adb6410dab4606a4f26a942aed02fb2f55387/src/jdk.httpserver/share/classes/sun/net/httpserver/ExchangeImpl.java#L281 >>>> >>>> This means that after the handler runs and it sends data - e.g. /hello >>>> sends “hello” on the connection, the connection will stall due to the >>>> Nagel algorithm - usually incurring a 50 ms delay. The stall occurs since >>>> the client will not see the expected data until after the delay, so it is >>>> unable to send the next (when reusing the same connection/HttpClient). >>>> >>>> You can set the TCP_NODELAY on the server to work-around this, but a >>>> better solution would be to override the flush() on the >>>> BufferedOutputStream to not flush() the underlying connection - i.e. only >>>> write the buffered bytes, or rework it a bit to only flush when there is >>>> no content to send. >>>>
