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.
Paolo
Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Dr. David Alan Gilbert <dave@treblig.org> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> --- util/qemu-thread-posix.c | 6 ++++++ util/qemu-thread-win32.c | 6 ++++++ 2 files changed, 12 insertions(+)
diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c index b1c127dbe3..afeac9ecad 100644 --- a/util/qemu-thread-posix.c +++ b/util/qemu-thread-posix.c @@ -22,6 +22,12 @@ #include <pthread_np.h> #endif +static void __attribute__((__constructor__(QEMU_CONSTRUCTOR_EARLY))) +qemu_thread_init(void) +{ + qemu_thread_set_name("main"); +} + static void error_exit(int err, const char *msg) { fprintf(stderr, "qemu: %s: %s\n", msg, strerror(err)); diff --git a/util/qemu-thread-win32.c b/util/qemu-thread-win32.c index 4d2d663a9a..8ca6429ad3 100644 --- a/util/qemu-thread-win32.c +++ b/util/qemu-thread-win32.c @@ -22,6 +22,12 @@ typedef HRESULT (WINAPI *pSetThreadDescription) (HANDLE hThread, static pSetThreadDescription SetThreadDescriptionFunc; static HMODULE kernel32_module; +static void __attribute__((__constructor__(QEMU_CONSTRUCTOR_EARLY))) +qemu_thread_init(void) +{ + qemu_thread_set_name("main"); +} + static bool load_set_thread_description(void) { static gsize _init_once = 0;
With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|