CPU usage spikes after several minutes of inactivity. This was observed a three times in the course of the last two hours. The last time this was observed, very few octave commands were actually executed and more debugger information was collected. Octave bits were compiled and installed using an hg clone made at Oct 7, 2012 at 17:40 Pacific Daylight Time. This is on an Ubuntu 12.04 LTS system. Native libraries were used, in general. The exception is gnulib, because the native library lacks isatty. The command sequence is short! The only command typed into the Command Window this last time consists of a single trivial octave instruction. GNU Octave. version 3.7.0+ Copyright (C) 2012 John W. Eaton and others. ... Octave was configured for "x86_64-unknown-linux-gnu". ... octave:1> eps ans = 2.2204e-16 octave:2> F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME CMD 0 S 1000 22936 22718 0 80 0 - 57039 wait pts/9 00:00:00 octave 1 t 1000 22937 22936 3 80 0 - 286176 ptrace ? 00:00:45 octave Attaching gdb to the octave process 22937 (gdb) info threads Id Target Id Frame 7 Thread 0x7fc9fbc8f700 (LWP 22938) "dconf worker" 0x00007fca11eba303 in __GI___poll (fds=, nfds=, timeout=) at ../sysdeps/unix/sysv/linux/poll.c:87 6 Thread 0x7fc9fb055700 (LWP 22939) "gdbus" 0x00007fca11eba303 in __GI___poll ( fds=, nfds=, timeout=) at ../sysdeps/unix/sysv/linux/poll.c:87 5 Thread 0x7fc9f8a50700 (LWP 22942) "octave" pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162 4 Thread 0x7fc9e9f8f700 (LWP 22943) "octave" 0x00007fca11eba303 in __GI___poll ( fds=, nfds=, timeout=) at ../sysdeps/unix/sysv/linux/poll.c:87 3 Thread 0x7fc9e973c700 (LWP 22944) "octave" 0x00007fca11eb88bd in read () at ../sysdeps/unix/syscall-template.S:82 2 Thread 0x7fc9d74ff700 (LWP 22946) "octave" 0x00007fca11ebf023 in select () at ../sysdeps/unix/syscall-template.S:82 * 1 Thread 0x7fca13824780 (LWP 22937) "octave" 0x00007fca11eba303 in __GI___poll ( fds=, nfds=, timeout=) at ../sysdeps/unix/sysv/linux/poll.c:87 (gdb) thread 7 [Switching to thread 7 (Thread 0x7fc9fbc8f700 (LWP 22938))] #0 0x00007fca11eba303 in __GI___poll (fds=, nfds=, timeout=) at ../sysdeps/unix/sysv/linux/poll.c:87 87 in ../sysdeps/unix/sysv/linux/poll.c (gdb) bt #0 0x00007fca11eba303 in __GI___poll (fds=, nfds=, timeout=) at ../sysdeps/unix/sysv/linux/poll.c:87 #1 0x00007fca0a4ca036 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #2 0x00007fca0a4ca49a in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #3 0x00007fc9fbc9498b in ?? () from /usr/lib/x86_64-linux-gnu/gio/modules/libdconfsettings.so #4 0x00007fca0a4eb9e5 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #5 0x00007fca0eebfe9a in start_thread (arg=0x7fc9fbc8f700) at pthread_create.c:308 #6 0x00007fca11ec5cbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112 #7 0x0000000000000000 in ?? () (gdb) thread 6 [Switching to thread 6 (Thread 0x7fc9fb055700 (LWP 22939))] #0 0x00007fca11eba303 in __GI___poll (fds=, nfds=, timeout=) at ../sysdeps/unix/sysv/linux/poll.c:87 87 in ../sysdeps/unix/sysv/linux/poll.c (gdb) bt #0 0x00007fca11eba303 in __GI___poll (fds=, nfds=, timeout=) at ../sysdeps/unix/sysv/linux/poll.c:87 #1 0x00007fca0a4ca036 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #2 0x00007fca0a4ca49a in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #3 0x00007fca02734406 in ?? () from /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0 #4 0x00007fca0a4eb9e5 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #5 0x00007fca0eebfe9a in start_thread (arg=0x7fc9fb055700) at pthread_create.c:308 #6 0x00007fca11ec5cbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112 #7 0x0000000000000000 in ?? () (gdb) thread 5 [Switching to thread 5 (Thread 0x7fc9f8a50700 (LWP 22942))] #0 pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162 162 ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S: No such file or directory. (gdb) bt #0 pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162 #1 0x00007fca107f64db in QWaitCondition::wait(QMutex*, unsigned long) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4 #2 0x00007fca10181354 in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4 #3 0x00007fca107f5fcb in ?? () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4 #4 0x00007fca0eebfe9a in start_thread (arg=0x7fc9f8a50700) at pthread_create.c:308 #5 0x00007fca11ec5cbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112 #6 0x0000000000000000 in ?? () (gdb) thread 4 [Switching to thread 4 (Thread 0x7fc9e9f8f700 (LWP 22943))] #0 0x00007fca11eba303 in __GI___poll (fds=, nfds=, timeout=) at ../sysdeps/unix/sysv/linux/poll.c:87 87 ../sysdeps/unix/sysv/linux/poll.c: No such file or directory. (gdb) bt #0 0x00007fca11eba303 in __GI___poll (fds=, nfds=, timeout=) at ../sysdeps/unix/sysv/linux/poll.c:87 #1 0x00007fca0a4ca036 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #2 0x00007fca0a4ca164 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #3 0x00007fca109243bf in QEventDispatcherGlib::processEvents(QFlags) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4 #4 0x00007fca108f3c82 in QEventLoop::processEvents(QFlags) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4 #5 0x00007fca108f3ed7 in QEventLoop::exec(QFlags) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4 #6 0x00007fca107f2fa7 in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4 #7 0x00007fca108d39ff in ?? () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4 #8 0x00007fca107f5fcb in ?? () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4 #9 0x00007fca0eebfe9a in start_thread (arg=0x7fc9e9f8f700) at pthread_create.c:308 #10 0x00007fca11ec5cbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112 #11 0x0000000000000000 in ?? () (gdb) thread 3 [Switching to thread 3 (Thread 0x7fc9e973c700 (LWP 22944))] #0 0x00007fca11eb88bd in read () at ../sysdeps/unix/syscall-template.S:82 82 ../sysdeps/unix/syscall-template.S: No such file or directory. (gdb) bt #0 0x00007fca11eb88bd in read () at ../sysdeps/unix/syscall-template.S:82 #1 0x00007fca134b43ee in read (__nbytes=4096, __buf=0x7fc9e973ae30, __fd=) at /usr/include/x86_64-linux-gnu/bits/unistd.h:45 #2 SelfListener::run (this=0xd3f8d0) at qterminal/libqterminal/unix/SelfListener.cpp:30 #3 0x00007fca107f5fcb in ?? () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4 #4 0x00007fca0eebfe9a in start_thread (arg=0x7fc9e973c700) at pthread_create.c:308 #5 0x00007fca11ec5cbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112 #6 0x0000000000000000 in ?? () (gdb) thread 2 [Switching to thread 2 (Thread 0x7fc9d74ff700 (LWP 22946))] #0 0x00007fca11ebf023 in select () at ../sysdeps/unix/syscall-template.S:82 82 ../sysdeps/unix/syscall-template.S: No such file or directory. (gdb) bt #0 0x00007fca11ebf023 in select () at ../sysdeps/unix/syscall-template.S:82 #1 0x00007fca0b0fefd5 in ?? () from /lib/x86_64-linux-gnu/libreadline.so.6 #2 0x00007fca0b0ff215 in rl_read_key () from /lib/x86_64-linux-gnu/libreadline.so.6 #3 0x00007fca0b0ea0b1 in readline_internal_char () from /lib/x86_64-linux-gnu/libreadline.so.6 #4 0x00007fca0b0ea5f5 in readline () from /lib/x86_64-linux-gnu/libreadline.so.6 #5 0x00007fca11988ad4 in gnu_readline::do_readline (this=, prompt=..., eof=@0x7fc9d74fd7bf: false) at util/cmd-edit.cc:253 #6 0x00007fca1198bae9 in command_editor::readline (prompt=..., eof=@0x7fc9d74fd7bf: false) at util/cmd-edit.cc:925 #7 0x00007fca12ddbc73 in gnu_readline (s=..., force_readline=false) at interpfcn/input.cc:204 #8 0x00007fca12ddbf22 in interactive_input (s=..., force_readline=false) at interpfcn/input.cc:250 #9 0x00007fca12ddc30f in octave_gets () at interpfcn/input.cc:283 #10 get_user_input () at interpfcn/input.cc:354 #11 octave_read (buf=0x7fc9cc4d77c0 "", max_size=8192) at interpfcn/input.cc:376 #12 0x00007fca12b52219 in yy_get_next_buffer () at parse-tree/lex.cc:3087 #13 0x00007fca12b5ba34 in octave_lex () at parse-tree/lex.cc:2929 #14 0x00007fca12b66004 in octave_parse () at parse-tree/oct-parse.cc:2516 #15 0x00007fca12e2d8b9 in main_loop () at interpfcn/toplev.cc:583 #16 0x00007fca127361d5 in octave_execute_interpreter () at octave.cc:1021 #17 0x00007fca107f5fcb in ?? () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4 #18 0x00007fca0eebfe9a in start_thread (arg=0x7fc9d74ff700) at pthread_create.c:308 #19 0x00007fca11ec5cbd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112 #20 0x0000000000000000 in ?? () (gdb) thread 1 [Switching to thread 1 (Thread 0x7fca13824780 (LWP 22937))] #0 0x00007fca11eba303 in __GI___poll (fds=, nfds=, timeout=) at ../sysdeps/unix/sysv/linux/poll.c:87 87 ../sysdeps/unix/sysv/linux/poll.c: No such file or directory. (gdb) bt #0 0x00007fca11eba303 in __GI___poll (fds=, nfds=, timeout=) at ../sysdeps/unix/sysv/linux/poll.c:87 #1 0x00007fca0a4ca036 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #2 0x00007fca0a4ca164 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #3 0x00007fca109243bf in QEventDispatcherGlib::processEvents(QFlags) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4 #4 0x00007fca0fd1fd5e in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4 #5 0x00007fca108f3c82 in QEventLoop::processEvents(QFlags) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4 #6 0x00007fca108f3ed7 in QEventLoop::exec(QFlags) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4 #7 0x00007fca108f8f67 in QCoreApplication::exec() () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4 #8 0x00007fca134dd910 in octave_start_gui (argc=1, argv=) at src/octave-gui.cc:117 #9 0x00007fca11df376d in __libc_start_main (main=0x400860 , argc=1, ubp_av=0x7fff1e6b7648, init=, fini=, rtld_fini=, stack_end=0x7fff1e6b7638) at libc-start.c:226 #10 0x00000000004008f1 in _start ()