LTTng-UST, the Linux Trace Toolkit Next Generation Userspace Tracer, is port of the low-overhead tracing capabilities of the LTTng kernel tracer to user-space. The library "libust" enables tracing of applications and libraries.
Changelog: * Add backward compability for tracepoint API (still planned for deprecation, but should make the transition smoother). The API transition will happen when UST 2.0 is ready. There is no point in making multiple API breakage when unneeded. tracing qemu-kvm with UST is now working again with UST 0.15 (0.14 did break it). Project website: http://lttng.org/ust/ Download link: http://lttng.org/files/ust/releases/ (please refer to the UST Manual for installation instructions) A quick walkthrough for tracing kvm-qemu with UST: git clone git://git.lttng.org/userspace-rcu.git (install: see README) git clone git://git.lttng.org/ust.git (install: see README) In my case, I enabled qemu_malloc, qemu_realloc, qemu_free, qemu_memalign, qemu_vmalloc, qemu_vfree by editing the "trace-events" file in the toplevel source directory (this file is qemu-specific, not the usual interface UST provides): # qemu-malloc.c qemu_malloc(size_t size, void *ptr) "size %zu ptr %p" qemu_realloc(void *ptr, size_t size, void *newptr) "ptr %p size %zu newptr %p" qemu_free(void *ptr) "ptr %p" # osdep.c qemu_memalign(size_t alignment, size_t size, void *ptr) "alignment %zu size %zu ptr %p" qemu_vmalloc(size_t size, void *ptr) "size %zu ptr %p" qemu_vfree(void *ptr) "ptr %p" ./configure --enable-trace-backend=ust make ldd x86_64-softmmu/qemu-system-x86_64 ... libust.so.0 => /usr/local/lib/libust.so.0 (0x00007fa39fc74000) (it's linked with libust) usttrace x86_64-softmmu/qemu-system-x86_64 ... stop it (ctrl-c) See resulting trace in: $HOME/.usttraces/hostname-timestamp UST 0.15 traces can be viewed with lttv: git clone git://git.lttng.org/lttv.git (install: view README) To view the trace (e.g.): % lttv -m textDump -t % /home/compudj/.usttraces/ok-20110715144748823020811/32575_5629652727107472206 ... ust.qemu_free: 1552840.525993542 (/home/compudj/.usttraces/ok-20110715144748823020811/32575_5629652727107472206/ust_6), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ptr = 0x1187680 } ust.qemu_free: 1552840.525994061 (/home/compudj/.usttraces/ok-20110715144748823020811/32575_5629652727107472206/ust_6), 0, 0, , , 0, 0x0, MODE_UNKNOWN { ptr = 0x1187660 } -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com
