<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_RESOLVED bz_closed" title="RESOLVED FIXED - KDE Konsole very slow scrolling with TearFree and QT graphics system native" href="https://bugs.freedesktop.org/show_bug.cgi?id=77436#c158">Comment # 158</a> on <a class="bz_bug_link bz_status_RESOLVED bz_closed" title="RESOLVED FIXED - KDE Konsole very slow scrolling with TearFree and QT graphics system native" href="https://bugs.freedesktop.org/show_bug.cgi?id=77436">bug 77436</a> from <a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> Chris Wilson</a> <pre>Yours @ 1024x768: Testing a8r8g8b8 with Src: ref=0.273359, out=0.420982 Testing x8r8g8b8 with Src: ref=0.273589, out=0.421422 Testing a8r8g8b8 with Over: ref=0.775864, out=0.441080 Testing x8r8g8b8 with Over: ref=0.274387, out=0.416628 Mine @ 1024x768: Testing a8r8g8b8 with Src: ref=0.870605, out=0.593283 Testing x8r8g8b8 with Src: ref=0.858216, out=0.589730 Testing a8r8g8b8 with Over: ref=1.947748, out=0.767362 Testing x8r8g8b8 with Over: ref=0.857667, out=0.586849 Looking at the reference, which uses pure software rasterisation, your cpu/memory is a little over 2x faster (indeed that is most likely due to the dual channel advantage you have). But it seems that the GPU is completely memory bandwidth limited. Comparing Over with argb, which is the only operation there that does perform a read from dst and blend with src before writing, we do expect to see a significant impact from the extra read. Can you please 'cat /sys/kernel/debug/dri/0/i915_ring_freq_table' and 'cat /proc/cpuinfo'</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>