2 Feb
2021
2 Feb
'21
3:13 p.m.
Daniel Vetter writes:
Just a quick comment on this: Since most framebuffers are write-combining, and reads from that tend to be ~3 orders of magnitude slower than writes (at least on the pile of machines I looked at here, there's big differences, and some special streaming cpu instructions to make the reading side not so slow).
So scrolling by copying tends to be significantly slower than just redrawing everything.
I know this was the case years ago with AGP as iirc, it doubled ( 4x, 8x ) the PCI clock rate but only for writes wasn't it? I thought this was no longer an issue with PCIe, but if it is, then I guess I'll go ahead with cleaning up the dead code and having it re-render with the larger text buffer.