[PATCH 3/3] exa/mixed: Exclude frontbuffer from deferred pixmap handling.

Michel Dänzer michel at daenzer.net
Mon Dec 20 07:05:07 PST 2010


On Mon, 2010-12-20 at 15:54 +0100, Maarten Maathuis wrote: 
> 2010/12/20 Michel Dänzer <michel at daenzer.net>:
> > On Mon, 2010-12-20 at 15:46 +0100, Maarten Maathuis wrote:
> >> 2010/12/14 Michel Dänzer <michel at daenzer.net>:
> >> > On Mon, 2010-12-13 at 19:42 +0100, Maarten Maathuis wrote:
> >> >> - Apps like xterm can trigger a lot of fallback rendering.
> >> >> - This can lead to (annoyingly) high latencies, because you
> >> >>   have to wait for the block handler.
> >> >> - You need a driver that doesn't directly access the front
> >> >>   buffer to trigger this (NV50+ nouveau for example).
> >> >> - Repeatingly doing dmesg on an xterm with a bitmap font
> >> >>   will reveal that you never see part of the text.
> >> >> - I have recieved at least one complaint in the past of slow
> >> >>   terminal performance, which was related to core font
> >> >>   rendering.
> >> >> - This does sacrifice some throughput, not sure how much,
> >> >
> >> > Shouldn't be hard to measure.
> >>
> >> I did a little test (catting a saved copy of dmesg) and the throughput
> >> loss is about 25%.
> >
> > What are the absolute numbers?
> 
> Roughly 250 ms vs 330 ms (error margin is about 20-30 ms if i had to guess).

That seems rather inaccurate, can you try something at least an order of
magnitude bigger?


-- 
Earthling Michel Dänzer           |                http://www.vmware.com
Libre software enthusiast         |          Debian, X and DRI developer


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