[Qemu-devel] Fwd: QEMU Simple tracing doesn't work

[Ivan Korolev]

Hello,

Seems like nobody at qemu-discuss has any clue about this topic, so I'm 
forwarding my question to qemu-devel.


-------- Forwarded Message --------
Subject:        QEMU Simple tracing doesn't work
Date:   Tue, 4 Oct 2016 17:11:04 +0300
From:   Ivan Korolev <address@hidden>
To:     address@hidden



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