Hi Nam,
I pushed the following changes to my branch. It'd be great if you
could give it a shot:
git://github.com/noahdesu/ceph.git wip-java-cephfs
- Throws CephNotMountedException when the client is not mounted
- Adds synchronization to the native code
Thanks,
Noah
On Thu, May 31, 2012 at 6:08 AM, Nam Dang <namd@xxxxxxxxxxxxxxxxxx> wrote:
>
> Dear all,
>
> I am running a small benchmark for Ceph with multithreading and
> cephfs-java API.
> I encountered this issue even when I use only two threads, and I used
> only open file and creating directory operations.
>
> The piece of code is simply:
> String parent = filePath.substring(0, filePath.lastIndexOf('/'));
> mount.mkdirs(parent, 0755); // create parents if the path does not exist
> int fileID = mount.open(filePath, CephConstants.O_CREAT, 0666); //
> open the file
>
> Each thread mounts its own ceph mounting point (using
> mount.mount(null)) and I don't have any interlocking mechanism across
> the threads at all.
> It appears the error is SIGSEGV sent off by libcepfs. The message is as
> follows:
>
> #
> # A fatal error has been detected by the Java Runtime Environment:
> #
> # SIGSEGV (0xb) at pc=0x00007ff6af978d39, pid=14063, tid=140697400411904
> #
> # JRE version: 6.0_26-b03
> # Java VM: Java HotSpot(TM) 64-Bit Server VM (20.1-b02 mixed mode
> linux-amd64 compressed oops)
> # Problematic frame:
> # C [libcephfs.so.1+0x139d39] Mutex::Lock(bool)+0x9
> #
> # An error report file with more information is saved as:
> # /home/namd/cephBench/hs_err_pid14063.log
> #
> # If you would like to submit a bug report, please visit:
> # http://java.sun.com/webapps/bugreport/crash.jsp
> # The crash happened outside the Java Virtual Machine in native code.
> # See problematic frame for where to report the bug.
>
> I have also attached the hs_err_pid14063.log for your reference.
> An excerpt from the file:
>
> Stack: [0x00007ff6aa828000,0x00007ff6aa929000],
> sp=0x00007ff6aa9274f0, free space=1021k
> Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native
> code)
> C [libcephfs.so.1+0x139d39] Mutex::Lock(bool)+0x9
>
> Java frames: (J=compiled Java code, j=interpreted, Vv=VM code)
> j com.ceph.fs.CephMount.native_ceph_mkdirs(JLjava/lang/String;I)I+0
> j com.ceph.fs.CephMount.mkdirs(Ljava/lang/String;I)V+6
> j
> Benchmark$CreateFileStats.executeOp(IILjava/lang/String;Lcom/ceph/fs/CephMount;)J+37
> j Benchmark$StatsDaemon.benchmarkOne()V+22
> j Benchmark$StatsDaemon.run()V+26
> v ~StubRoutines::call_stub
>
> So I think the probably may be due to the locking mechanism of ceph
> internally. But Dr. Weil previously answered my email stating that the
> mounting is done independently so multithreading should not lead to
> this problem. If there is anyway to work around this, please let me
> know.
>
> Best regards,
>
> Nam Dang
> Email: namd@xxxxxxxxxxxxxxxxxx
> HP: (+81) 080-4465-1587
> Yokota Lab, Dept. of Computer Science
> Tokyo Institute of Technology
> Tokyo, Japan
--
To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
