On Tue, Apr 23, 2013 at 05:31:07PM +0900, Namhyung Kim wrote: > From: Namhyung Kim <namhyung....@lge.com> > > The ftrace record command is for saving raw ftrace buffer contents > which can be get from per_cpu/cpuX/trace_pipe_raw. > > Since ftrace events are generated very frequently so single thread for > recording mostly resulted in buffer overruns. Thus it uses per-cpu > recorder thread to prevent such cases and they save the contents to > their own files. > > These per-cpu data files are saved in a directory so that they can be > easily found when needed. I chose the default directory name as > "perf.data.dir" and the first two (i.e. "perf.data") can be changed > with -o option. The structure of the directory looks like: > > $ tree perf.data.dir > perf.data.dir/ > |-- perf.header > |-- trace-cpu0.buf > |-- trace-cpu1.buf > |-- trace-cpu2.buf > `-- trace-cpu3.buf > > In addition to trace-cpuX.buf files, it has perf.header file also. > The perf.header file is compatible with existing perf.data format and > contains usual event information, feature mask and sample data. The > sample data is synthesized to indicate given cpu has a record file.
I got following lockup for record command: # ./perf --no-pager ftrace record ls ... hangs in other terminal: # pstack 14237 Thread 2 (Thread 0x7f3f1aa1d700 (LWP 14241)): #0 0x0000003cec20b595 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0 #1 0x0000000000446ebe in record_ftrace_raw_buffer (arg=0x21f9ce0) at builtin-ftrace.c:451 #2 0x0000003cec207d14 in start_thread () from /lib64/libpthread.so.0 #3 0x0000003cebaf168d in clone () from /lib64/libc.so.6 Thread 1 (Thread 0x7f3f1ba209c0 (LWP 14237)): #0 0x0000003cec208e60 in pthread_join () from /lib64/libpthread.so.0 #1 0x0000000000449c8c in do_ftrace_record (ftrace=ftrace@entry=0x7fff1377d240) at builtin-ftrace.c:682 #2 0x000000000044a57b in __cmd_ftrace_record (argv=0x7fff1377d818, argc=<optimized out>, ftrace=0x7fff1377d240) at builtin-ftrace.c:1535 #3 cmd_ftrace (argc=2, argv=0x7fff1377d818, prefix=<optimized out>) at builtin-ftrace.c:1655 #4 0x000000000041a763 in run_builtin (p=p@entry=0x7d58a0, argc=argc@entry=3, argv=argv@entry=0x7fff1377d818) at perf.c:320 #5 0x0000000000419faf in handle_internal_command (argv=0x7fff1377d818, argc=3) at perf.c:377 #6 run_argv (argv=0x7fff1377d600, argcp=0x7fff1377d60c) at perf.c:421 #7 main (argc=3, argv=0x7fff1377d818) at perf.c:522 jirka -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
