[Qemu-discuss] QEMU Simple tracing doesn't work

[Ivan Korolev]

Hello,

I'm trying to run QEMU with simple tracing feature, but something is wrong, because it always produces a file of 24 bytes long.

What I've done:

1) Cloned QEMU sources for version v2.7.0 release

2) Removed "[disabled]" tag in qemu/trace-events for guest_user_syscall_ret, guest_user_syscall, guest_mem_before prototypes

3) Ran the following:

./configure --enable-trace-backends=simple

make

sudo make install

4) Ran my VM:

qemu-system-i386 -trace enable:guest_user_syscall* -hda backup.qcow2 -m 512M -net user,hostfwd=::10000-:22 -net nic -no-reboot -snapshot -monitor stdio

5) Checked that tracepoints are enabled (ran "info trace-points" in monitor's console):

...

guest_user_syscall_ret : state 1
guest_user_syscall : state 1
...

6) Made some actions in the VM (creating/deleting of files/folders) and turned off the VM

When I finished with it, there was a file trace-29758 that is only 24 bytes long and simpletrace.py doesn't produce anything from it.

Could you please tell me what I'm doing wrong?

-- 
Regards,
Ivan Korolev