Re: [Qemu-devel] 100% host cpu with gtk3

[Daniel P . Berrangé]

On Wed, Jun 06, 2018 at 06:43:57PM +0800, Fam Zheng wrote:
> Hi Gerd,
> 
> When using the gtk frontend, it seems there is a busy loop in libgtk 
> repeatedly
> calling recvmsg, causing 100% cpu on the main thread. This started to appear
> after I upgraded to Fedora 28. Is this a known problem?
> 
> Any hints on how to track it down?

GLib has systemtap probes registered in its dispatch code. These probes
will include the name of the GSource. You could possibly use this to
identify which GSource is firing too often.

eg in gmain.c in glib code there are these events to hook into:

          TRACE (GLIB_MAIN_BEFORE_DISPATCH (g_source_get_name (source), source,
                                            dispatch, callback, user_data));
          need_destroy = !(* dispatch) (source, callback, user_data);
          TRACE (GLIB_MAIN_AFTER_DISPATCH (g_source_get_name (source), source,
                                           dispatch, need_destroy));



Regards,
Daniel
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