On 1/9/26 12:52, Daniel P. Berrangé wrote:
On Fri, Jan 09, 2026 at 12:45:03PM +0100, Paolo Bonzini wrote:
On 1/8/26 18:03, Daniel P. Berrangé wrote:
The default main thread name is undefined, so use a constructor to
explicitly set it to 'main'. This constructor is marked to run early
as the thread name is intended to be used in error reporting / logs
which may be triggered very early in QEMU execution.
At least on Linux I don't think we want to call the pthread function.
Since pthread_setname_np writes to /proc/self/task/tid/comm, wouldn't that
cause ps to show qemu processes as "main" instead of "qemu" or "qemu-kvm"?
Hmmm, it depends on the 'ps' options you use:
$ ./build/qemu-system-x86_64 &
[3] 3859009
⚙️ [oci:fedora-43 qemu]$ ps | grep 3859009
3859009 pts/10 00:00:04 main
⚙️ [oci:fedora-43 qemu]$ ps -a | grep 3859009
3859009 pts/10 00:00:03 main
⚙️ [oci:fedora-43 qemu]$ ps -ax | grep 3859009
3859009 pts/10 Sl 0:03 ./build/qemu-system-x86_64
⚙️ [oci:fedora-43 qemu]$ ps -au | grep 3859009
berrange 3859009 8.6 0.1 3893224 123700 pts/10 Sl 11:49 0:04
./build/qemu-system-x86_64
⚙️ [oci:fedora-43 qemu]$ ps -af | grep 3859009
berrange 3859009 2085609 8 11:49 pts/10 00:00:04 ./build/qemu-system-x86_64
⚙️ [oci:fedora-43 qemu]$ ps -axuwf | grep 3859009
berrange 3859009 53.4 0.1 3905536 124108 pts/10 Sl 11:49 0:03 | \_
./build/qemu-system-x86_64
and I hadn't noticed since I always use one of the latter
sets of options that give the true name.
FWIW "top" also changes its process name to "main"; there's precedent
for Firefox *not* changing it:
$ ps -o "%c" $(pidof firefox)
COMMAND
firefox
forkserver
Socket Process
Privileged Cont
...
Since we can't really know how the COMM is being used by monitoring
tools, and there's a simple workaround within QEMU, I'd prefer avoiding
this. Sorry for not spotting it earlier.
Paolo
