Date: Thu, 26 Mar 2015 16:42:57 -0400 From: Jung-uk Kim <jkim@FreeBSD.org> To: Johannes Dieterich <dieterich.joh@gmail.com>, freebsd-java@freebsd.org Subject: Re: dtrace, jstack and lang/openjdk7 or 8 Message-ID: <55146F51.3030404@FreeBSD.org> In-Reply-To: <CABquGzWu7Y2v80D8EOfQ8QR9T_hCb9T9t6a%2BkjissxEsKbjLCA@mail.gmail.com> References: <CABquGzWu7Y2v80D8EOfQ8QR9T_hCb9T9t6a%2BkjissxEsKbjLCA@mail.gmail.com>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 03/25/2015 19:02, Johannes Dieterich wrote: > Hi, > > I am currently trying to get dtrace to work with either > java/openjdk7 or java/openjdk8 (as per Brendan Gregg's howto: > http://www.brendangregg.com/blog/2014-06-12/java-flame-graphs.html). > > Unfortunately, I get exactly what he describes: I am missing > everything inside the JVM. I suspect this has to do with jstack() > not working. The bundled jstack executable (yes, I know that they > are only vaguely related) also seems to work only so-so. Basically, > I can get a working stack trace without a variable, with -l, but > not with -m, and not with -F. It causes exceptions like this: > > $ /usr/local/openjdk7/bin/jstack -m 84749 ... > So, what I am asking is: anybody out there got a working setup for > dtrace+openjdk on FreeBSD? If so, it would be fantastic if you > could post the necessary steps! jstack from java/openjdk8 works fine AFAICT. Unfortunately, dtrace is unimplemented for FreeBSD. BTW, 'jstack -m <pid>' is invalid command, i.e., it does not work with a running process. You need to set '-F' option to force it. % /usr/local/openjdk8/bin/jstack Usage: jstack [-l] <pid> (to connect to running process) jstack -F [-m] [-l] <pid> (to connect to a hung process) jstack [-m] [-l] <executable> <core> (to connect to a core file) jstack [-m] [-l] [server_id@]<remote server IP or hostname> (to connect to a remote debug server) Options: -F to force a thread dump. Use when jstack <pid> does not respond (process is hung) -m to print both java and native frames (mixed mode) -l long listing. Prints additional information about locks -h or -help to print this help message Jung-uk Kim -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBCAAGBQJVFG9MAAoJEHyflib82/FG4F0H/3Z+5fTXMzQYBCeWGMZicjMB 092HOaXctRZ5P+I5HZO199bfFLffV6Pu1pd2/jjguOqkmF4eVL6AXwQBglg19RPs BEwhSLRLhuWc11XyikE2RG3PvvDRvhXl6AeqtKkcUi4LedjS3BlqmlGpTorJzpO3 OqarnzGMyAHPS5QxPPUcASG4B+la6o1sVn94UiynUWnd3yXTe4uE4Ed4YeV2oBXh BGVLhTdsWoamNpMwX9JrOMNwRPahYpoDCjeC2jlKPGPCXQiTWthlupLidXuKUI/a OJi+VSAzNPMx5s1p2JSKwAp+tT6oX8BaFK0zA+J6cyBcBqqbWvA6LV+v9f8c/5A= =x1pC -----END PGP SIGNATURE-----
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