AFAIK Harmony snapshots will not work on pre-2.6 kernels anyway since DRLVM has some issues with it. For details please see an old discussion at [1] and especially Salikh's reply at [2]. As far as I understand the issue is still relevant for the current version of DRLVM, at least I haven't seen any discussions about it since then.
[1] http://gmane.comp.java.harmony.devel/23045 [2] http://gmane.comp.java.harmony.devel/23167 With Best Regards, Alexei 2007/10/8, Alexei Fedotov <[EMAIL PROTECTED]>: > Hello Jimmy, > > > However I have a concern that, shall we offer a build for the > > users with a previous version of Linux kernel 2.6 (maybe there's a lot > > of them who also require JDK)? > > I believe we need to look forward and take advantage of new OS and > hardware features. We offer stable releases (harmony trunks) of older > versions and may support and patch them if a customer requests. But > generally we should be going forward and becoming more effective. > > Thanks! > > On 10/8/07, Jimmy,Jing Lv <[EMAIL PROTECTED]> wrote: > > Hi, > > > > It's really cool ! :) > > > > However I have a concern that, shall we offer a build for the > > users with a previous version of Linux kernel 2.6 (maybe there's a lot > > of them who also require JDK)? IMHO, at least we can reserve a copy of > > previous implementation of select for that? > > We may modify the makefile or build.xml for that? > > > > 2007/10/4, Aleksey Shipilev <[EMAIL PROTECTED]>: > > > Hi again, > > > > > > I have updated the JIRA [1] with the final patch, all known > > > performance issues were resolved. I have also run extensive experiment > > > for measuring the performance of Selector.selectNow() operation on > > > current and epoll-based implementations comparing to Sun 1.6.0. You > > > might find the results in the JIRA attachment: comparison of current > > > and epoll-based implementation [2]. > > > > > > This implementation successfully passes JUnit tests and simple > > > workloads. It's also does not change anything in the classlib (not > > > saying about makefiles), additional option should be specified to > > > enable epoll functionality, so it's safe to apply this patch at any > > > time. > > > > > > BTW, as I found not so long ago, epoll-based Selector is the main > > > improvement for java.nio.* in Sun 1.6.0 classlib [3], and we're going > > > neck and neck with them [4] :) > > > > > > Thanks, > > > Aleksey Shipilev, > > > ESSD, Intel > > > > > > [1] https://issues.apache.org/jira/browse/HARMONY-4879 > > > [2] https://issues.apache.org/jira/secure/attachment/12367060/2000-all.png > > > [3] > > > http://java.sun.com/javase/6/docs/technotes/guides/io/enhancements.html > > > [4] > > > https://issues.apache.org/jira/secure/attachment/12367060/2000-best.png > > > > > > On 10/1/07, Aleksey Shipilev <[EMAIL PROTECTED]> wrote: > > > > Hi all, > > > > > > > > I would like to present the epoll()-based java.nio.channels.Selector > > > > for Harmony. Epoll facility [1] was developed as the part on Linux > > > > Kernel starting from version 2.5.44, and its interface was finalized > > > > starting before 2.6.x kernels. Epoll is generally driven by callbacks > > > > inside the kernel and thus it strives to be O(1), whereas legacy > > > > poll() and select() are driven by traversing linked lists and thus > > > > being O(n). > > > > > > > > You can find draft implementation at HARMONY-4879 [2]. This version is > > > > ready to play, but not intended for inclusion, since there are a > > > > couple of performance problems persist (like possible O(n^2) at > > > > processSelectResults()). I will try to eliminate them in several days. > > > > However, this patch successfully passes JUnit tests and might be ready > > > > to be tried on some networking-heavy workloads. > > > > > > > > Speaking about performance results, simple test which registers 2000 > > > > channels on one Selector and then continuously calls selectNow() > > > > reveals this: > > > > > > > > Harmony-r576670: > > > > connect time: 100538 msecs > > > > selectNow() time (10000 times): 27777 msecs > > > > > > > > Harmony-r576670 + HARMONY-4879: > > > > connect time: 832 msecs > > > > selectNow() time (10000 times): 87 msecs > > > > > > > > Speedups: > > > > connect: 120x > > > > selectNow(): 320x > > > > > > > > More details are in JIRA. > > > > > > > > Is someone interested in the topic? > > > > I would like to collaborate with you then - to prevent duplication of > > > > work :) > > > > > > > > [1] http://lse.sourceforge.net/epoll/index.html > > > > [2] https://issues.apache.org/jira/browse/HARMONY-4879
