On Wed, Sep 4, 2019 at 8:53 AM Thomas Zimmermann <tzimmermann@xxxxxxx> wrote: > > Hi > > Am 04.09.19 um 08:27 schrieb Feng Tang: > >> Thank you for testing. But don't get too excited, because the patch > >> simulates a bug that was present in the original mgag200 code. A > >> significant number of frames are simply skipped. That is apparently the > >> reason why it's faster. > > > > Thanks for the detailed info, so the original code skips time-consuming > > work inside atomic context on purpose. Is there any space to optmise it? > > If 2 scheduled update worker are handled at almost same time, can one be > > skipped? > > To my knowledge, there's only one instance of the worker. Re-scheduling > the worker before a previous instance started, will not create a second > instance. The worker's instance will complete all pending updates. So in > some way, skipping workers already happens. So I think that the most often fbcon update from atomic context is the blinking cursor. If you disable that one you should be back to the old performance level I think, since just writing to dmesg is from process context, so shouldn't change. https://unix.stackexchange.com/questions/3759/how-to-stop-cursor-from-blinking Bunch of tricks, but tbh I haven't tested them. In any case, I still strongly advice you don't print anything to dmesg or fbcon while benchmarking, because dmesg/printf are anything but fast, especially if a gpu driver is involved. There's some efforts to make the dmesg/printk side less painful (untangling the console_lock from printk), but fundamentally printing to the gpu from the kernel through dmesg/fbcon won't be cheap. It's just not something we optimize beyond "make sure it works for emergencies". -Daniel > > Best regards > Thomas > > > > > Thanks, > > Feng > > > >> > >> Best regards > >> Thomas > > _______________________________________________ > > dri-devel mailing list > > dri-devel@xxxxxxxxxxxxxxxxxxxxx > > https://lists.freedesktop.org/mailman/listinfo/dri-devel > > > > -- > Thomas Zimmermann > Graphics Driver Developer > SUSE Linux GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany > GF: Felix Imendörffer, Mary Higgins, Sri Rasiah > HRB 21284 (AG Nürnberg) > > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
