Re: EWMH 1.6 with frame synchronization?
On Fri, Nov 25, 2022 at 06:47:57PM +0800, Po Lu wrote: > Jonas Ådahl writes: > > > I understand that, but at least you can point at the fact that it has > > been implemented and used in GNOME for more or less a decade already. > > Well, that apparently does not hold water in the world of the KWin > developers, who say: > > https://www.mail-archive.com/kde-bugs-dist@kde.org/msg672095.html > > Specifically: > > > We are not introducing big changes into X11 at this time especially > > for something non standard. > Not all that surprised, kwin is as many other spending their effort on Wayland rather than X11, where this issue doesn't exist to begin with. Jonas
Re: EWMH 1.6 with frame synchronization?
Jonas Ådahl writes: > I understand that, but at least you can point at the fact that it has > been implemented and used in GNOME for more or less a decade already. Well, that apparently does not hold water in the world of the KWin developers, who say: https://www.mail-archive.com/kde-bugs-dist@kde.org/msg672095.html Specifically: > We are not introducing big changes into X11 at this time especially > for something non standard.
Re: EWMH 1.6 with frame synchronization?
On Fri, Nov 25, 2022 at 06:26:40PM +0800, Po Lu wrote: > Jonas Ådahl writes: > > > Perhaps open a merge request adding it to > > https://gitlab.freedesktop.org/xdg/xdg-specs/-/blob/master/wm-spec/wm-spec.xml, > > but you should probably familiarize with what happened the last time it > > was attempted, which was in 2011: > > > > https://mail.gnome.org/archives/wm-spec-list/2011-October/msg6.html > > AFAICT from that discussion, the effort just fizzled out. The main/only > problem with the approach you outlined is that I don't have a > gitlab.freedesktop.org account, and the lawyers at my organization are > not keen to let me get one. > > If I were to add the clarifications to the monotonic clock handling and > send you a patch to wm-spec.xml, could you please open a merge request > on my behalf? I don't really have the time and motivation to do the work required move the frame timings spec anywhere more formal. I can try to help trying to interpret the mutter and gtk implementation if you have any questions anyhow. > > > But you can just as well go and implement it anyway, if you need this > > kind of frame synchronization on X11; it's unrealistic that adding it to > > wm-spec.xml would mean any changes were to be made to it anyway. > > It'd really be easier for me to work on this if it were in the wm-spec. > That way, I could point and say "that's a standard!", instead of "that's > floating somewhere in a bowl of fish soup!" I understand that, but at least you can point at the fact that it has been implemented and used in GNOME for more or less a decade already. Jonas > > Thanks.
Re: EWMH 1.6 with frame synchronization?
Jonas Ådahl writes: > Perhaps open a merge request adding it to > https://gitlab.freedesktop.org/xdg/xdg-specs/-/blob/master/wm-spec/wm-spec.xml, > but you should probably familiarize with what happened the last time it > was attempted, which was in 2011: > > https://mail.gnome.org/archives/wm-spec-list/2011-October/msg6.html AFAICT from that discussion, the effort just fizzled out. The main/only problem with the approach you outlined is that I don't have a gitlab.freedesktop.org account, and the lawyers at my organization are not keen to let me get one. If I were to add the clarifications to the monotonic clock handling and send you a patch to wm-spec.xml, could you please open a merge request on my behalf? > But you can just as well go and implement it anyway, if you need this > kind of frame synchronization on X11; it's unrealistic that adding it to > wm-spec.xml would mean any changes were to be made to it anyway. It'd really be easier for me to work on this if it were in the wm-spec. That way, I could point and say "that's a standard!", instead of "that's floating somewhere in a bowl of fish soup!" Thanks.
Re: EWMH 1.6 with frame synchronization?
On Fri, Nov 25, 2022 at 05:13:45PM +0800, Po Lu wrote: > Jonas Ådahl writes: > > > The confusion is that the timestamps can't be generated "directly" but > > must still wrap in the same way X server timestamps. In other words, > > it's fine to source your timestamps directly from the monotonic clock, > > if it's concluded that the X server uses it, but you must still make > > sure you wrap the values as if the milli second part is encoded using a > > unsigned 32 bit integer. Mutter got this wrong in the past, and it > > results in wierd bugs with frozen GTK frame clocks after almost two > > months of uptime. > > Yes, that's what I said ought to be clarified. I'm sorry I wasn't too > clear there. > > So aside from that, what else is preventing the protocol from being > included in the wm-spec? I have no idea. > And how can I help get it included? Perhaps open a merge request adding it to https://gitlab.freedesktop.org/xdg/xdg-specs/-/blob/master/wm-spec/wm-spec.xml, but you should probably familiarize with what happened the last time it was attempted, which was in 2011: https://mail.gnome.org/archives/wm-spec-list/2011-October/msg6.html But you can just as well go and implement it anyway, if you need this kind of frame synchronization on X11; it's unrealistic that adding it to wm-spec.xml would mean any changes were to be made to it anyway. Jonas > > Thanks a lot in advance.
Re: EWMH 1.6 with frame synchronization?
Jonas Ådahl writes: > The confusion is that the timestamps can't be generated "directly" but > must still wrap in the same way X server timestamps. In other words, > it's fine to source your timestamps directly from the monotonic clock, > if it's concluded that the X server uses it, but you must still make > sure you wrap the values as if the milli second part is encoded using a > unsigned 32 bit integer. Mutter got this wrong in the past, and it > results in wierd bugs with frozen GTK frame clocks after almost two > months of uptime. Yes, that's what I said ought to be clarified. I'm sorry I wasn't too clear there. So aside from that, what else is preventing the protocol from being included in the wm-spec? And how can I help get it included? Thanks a lot in advance.
Re: EWMH 1.6 with frame synchronization?
On Fri, Nov 25, 2022 at 03:18:36PM +0800, Po Lu wrote: > Po Lu writes: > > > Owen Taylor has a frame synchronization protocol for compositing > > managers: https://fishsoup.net/misc/wm-spec-synchronization.html. > > > > It is currently only supported by Mutter and cannot be found outside his > > blog. Present does not quite work for this purpose, as the "present > > redirection" code was never finalized. Is anyone interested in > > releasing a new version of the wm-spec with the frame synchronization > > protocol? I'd be more comfortable writing code to use it, and maybe > > implementing it in more compositors, if it was specified in the actual > > wm-spec. > > > > Thanks. > > One clarification in the protocol I'd like to see is for the behavior > when the X server time overflows to be clarified. Right now, Mutter > simply uses the X server time to generate the millisecond part of > high-precision timestamps when the overflow happens, so that is what X > clients expect. I think the protocol should be clarified along those > lines as well. It's already relatively clearly specified, even with simple formula illustrating how the timestamps look: > For timestamps, the timestamp has the form (x_server_timestamp) * 1000 > + microsecond_value. That leaves little room for interpretation. What could be improved is the following part: > In this case, high precision times can be generated directly, and two > clients such will be able to exchange timestamps with sub-millisecond > accuracy. The confusion is that the timestamps can't be generated "directly" but must still wrap in the same way X server timestamps. In other words, it's fine to source your timestamps directly from the monotonic clock, if it's concluded that the X server uses it, but you must still make sure you wrap the values as if the milli second part is encoded using a unsigned 32 bit integer. Mutter got this wrong in the past, and it results in wierd bugs with frozen GTK frame clocks after almost two months of uptime. Jonas
Re: EWMH 1.6 with frame synchronization?
Po Lu writes: > Owen Taylor has a frame synchronization protocol for compositing > managers: https://fishsoup.net/misc/wm-spec-synchronization.html. > > It is currently only supported by Mutter and cannot be found outside his > blog. Present does not quite work for this purpose, as the "present > redirection" code was never finalized. Is anyone interested in > releasing a new version of the wm-spec with the frame synchronization > protocol? I'd be more comfortable writing code to use it, and maybe > implementing it in more compositors, if it was specified in the actual > wm-spec. > > Thanks. One clarification in the protocol I'd like to see is for the behavior when the X server time overflows to be clarified. Right now, Mutter simply uses the X server time to generate the millisecond part of high-precision timestamps when the overflow happens, so that is what X clients expect. I think the protocol should be clarified along those lines as well.
