On Tue, Nov 3, 2015 at 9:13 AM, 浩樊啊 <fanh2...@foxmail.com> wrote:
Please keep qemu-devel@nongnu.org on CC so the discussion stays on the mailing list where others can participate. > you mean that qemu-system-x86_64 ..... is a command to start a vm? > can I just start a vm by a xml file and then use qemu-system_x86_64 -trace > events=/tmp/events trace the vm? No, each QEMU process is a separate VM. Launching a new QEMU does not attach to an existing QEMU process. If you want to "attach" to a running QEMU process, you can use the SystemTap tracing backend. Make sure that your QEMU binary was built with ./configure --enable-trace-backend=dtrace (that is the case in Fedora and Red Hat-based distributions). Take a look at the /usr/share/systemtap/tapset/qemu-system-x86_64.stp tapset and SystemTap documentation here: https://sourceware.org/systemtap/wiki/AddingUserSpaceProbingToApps https://sourceware.org/systemtap/SystemTap_Beginners_Guide/ Stefan
