971bf15f26
XPending() will do a recvmsg() syscall if there are no items in the queue. In most cases, this is unnecessary because we know that there is data to be read of the connection or there are items already read which simply need to be processed. Discovering both of those conditions can be done without recvmsg() in the hot paths. Before this path, every iteration of the main loop had the potential to submit a recvmsg() syscall. This reduces that overhead drastically. XFlush() on the other-hand knows if it needs to write data or not and will do no IO in the case the buffer is empty. Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/3653 Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/4006>
99 lines
2.7 KiB
C
99 lines
2.7 KiB
C
/*
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* Copyright (C) 2023 Red Hat Inc.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "config.h"
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#include "meta-x11-event-source.h"
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typedef struct {
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GSource base;
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GPollFD event_poll_fd;
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Display *xdisplay;
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} MetaX11EventSource;
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static gboolean
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meta_x11_event_source_prepare (GSource *source,
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int *timeout)
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{
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MetaX11EventSource *event_source = (MetaX11EventSource *) source;
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*timeout = -1;
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XFlush (event_source->xdisplay);
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return XEventsQueued (event_source->xdisplay, QueuedAlready) > 0;
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}
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static gboolean
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meta_x11_event_source_check (GSource *source)
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{
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MetaX11EventSource *event_source = (MetaX11EventSource *) source;
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return (event_source->event_poll_fd.revents & G_IO_IN) != 0 ||
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XEventsQueued (event_source->xdisplay, QueuedAlready) > 0;
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}
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static gboolean
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meta_x11_event_source_dispatch (GSource *source,
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GSourceFunc callback,
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gpointer user_data)
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{
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MetaX11EventSource *event_source = (MetaX11EventSource *) source;
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MetaX11EventFunc event_func = (MetaX11EventFunc) callback;
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gboolean retval = G_SOURCE_CONTINUE;
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int pending;
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pending = XPending (event_source->xdisplay);
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while (retval == G_SOURCE_CONTINUE && pending > 0)
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{
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XEvent xevent;
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pending--;
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XNextEvent (event_source->xdisplay, &xevent);
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retval = event_func (&xevent, user_data);
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}
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return retval;
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}
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static GSourceFuncs meta_x11_event_source_funcs = {
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meta_x11_event_source_prepare,
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meta_x11_event_source_check,
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meta_x11_event_source_dispatch,
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};
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GSource *
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meta_x11_event_source_new (Display *xdisplay)
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{
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GSource *source;
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MetaX11EventSource *event_source;
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source = g_source_new (&meta_x11_event_source_funcs,
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sizeof (MetaX11EventSource));
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g_source_set_name (source, "[mutter] MetaX11Display events");
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event_source = (MetaX11EventSource *) source;
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event_source->xdisplay = xdisplay;
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event_source->event_poll_fd.fd = ConnectionNumber (xdisplay);
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event_source->event_poll_fd.events = G_IO_IN;
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g_source_add_poll (source, &event_source->event_poll_fd);
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return source;
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}
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