I’ll update my PR to remove the nodelay setting from those tests. I am going to change the PR to use UrlConnection rather than HttpClient as well.
> On Apr 8, 2024, at 7:10 AM, Robert Engels <reng...@ix.netcom.com> wrote: > > 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. >>>>>
