On 07/18/2012 10:06 AM, Lionel Elie Mamane wrote:
The issue *originally* reported in fdo#51239, which has been bumped to fdo#52170: in LibreOffice 3.5.2, much slower than "before", on GNU/Linux, but NOT on Windows. Unknown on Mac. Not entirely clear what "before" it is. *This* issue *could* be JVM-thread-attach/detach related, or some other "interaction between Java and C++" problem. My "hunch" in this direction is because it does not happen on MS Windows. So if you could look into it, even if only to rule it out, that would be useful.
Looked into it on x64 Linux master, against both an 1.7.0 openjdk (as included in Fedora 17) and a jre-6u33-linux-x64 downloaded from Oracle. In either case, it does take significantly to open the Sales Invoices table (from <https://bugs.freedesktop.org/attachment.cgi?id=63257>), and then it takes ages to jump to the end. However, I could not find anything obviously suspicious at the JVM level.
I locally reverted <http://cgit.freedesktop.org/libreoffice/core/commit/?id=bb59742bcf4883af5876a2ffadcc4a689e414b60> "Confine JDBC driver to thread-affine apartment for Java 6 performance" and then everything became even more slow, so it apparently is not the case that the effect of that fix has meanwhile regressed again.
I noticed that there are truckloads of calls to m_pVm->AttachCurrentThread from jvmaccess::VirtualMachine::attachThread (jvmaccess/source/virtualmachine.cxx). Such "outermost" calls into JNI (i.e., not recursively from a thread that is already in a JNI call, where jvmaccess::VirtualMachine::attachThread would be cheap) are always expensive (and the changes to the JVM that we tried to address with bb59742bcf4883af5876a2ffadcc4a689e414b60 only made them extra-extra expensive, when they already had been expensive). The LO database code is notorious for making truckloads of such expensive outermost JNI calls, but I do not know if this has increased substantially recently and so alone could explain any recent performance regressions.
Stephan _______________________________________________ LibreOffice mailing list LibreOffice@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/libreoffice
