On Wed, 10 Nov 2021 14:32:26 -0300 Igor Torrente <igormtorre...@gmail.com> wrote:
> Hi Pekka, > > On Tue, Nov 9, 2021 at 6:32 AM Pekka Paalanen <ppaala...@gmail.com> wrote: > > > > On Tue, 26 Oct 2021 08:34:00 -0300 > > Igor Torrente <igormtorre...@gmail.com> wrote: > > > > > Summary > > > ======= > > > This series of patches refactor some vkms components in order to introduce > > > new formats to the planes and writeback connector. > > > > > > Now in the blend function, the plane's pixels are converted to > > > ARGB16161616 > > > and then blended together. > > > > > > The CRC is calculated based on the ARGB1616161616 buffer. And if required, > > > this buffer is copied/converted to the writeback buffer format. > > > > > > And to handle the pixel conversion, new functions were added to convert > > > from a specific format to ARGB16161616 (the reciprocal is also true). > > > > > > Tests > > > ===== > > > This patch series was tested using the following igt tests: > > > -t ".*kms_plane.*" > > > -t ".*kms_writeback.*" > > > -t ".*kms_cursor_crc*" > > > -t ".*kms_flip.*" > > > > > > New tests passing > > > ------------------- > > > - pipe-A-cursor-size-change > > > - pipe-A-cursor-alpha-transparent > > > > > > Performance > > > ----------- > > > Following some optimization proposed by Pekka Paalanen, now the code > > > runs way faster than V1 and slightly faster than the current > > > implementation. > > > > > > | Frametime | > > > |:---------------:|:---------:|:--------------:|:------------:| > > > | implmentation | Current | Per-pixel(V1) | Per-line(V2) | > > > | frametime range | 8~22 ms | 32~56 ms | 6~19 ms | > > > | Average | 10.0 ms | 35.8 ms | 8.6 ms | > > > > Wow, that's much better than I expected. > > > > What is your benchmark? That is, what program do you use and what > > operations does it trigger to produce these measurements? What are the > > sizes of all the planes/buffers involved? What kind of CPU was this ran > > on? > > 1 and 2) I just measured the frametime of the IGT test ".*kms_cursor_crc*" > using jiffies. I Collected all the frametimes, put all of them into a > spreadsheet, calculated some values and drew some histograms. > > I mean, it is not the best benchmark, but at least give an idea of what > is happening. > > 3) The primary plane was 1024x768, but the cursor plane > varies between the tests. All XRGB_8888, if I'm not mistaken. > > 4) I tested it on a Qemu VM running on the Intel core i5 4440. ~3.3GHz Hi Igor, alright, that analysis sounds fine, even though varying cursor plane size is casting some ambiguity on the results. If you want to dig deeper into measuring this, I would suggest some scenarios if at all possible: - large primary plane and large cursor plane with 100% overlap, to measure the raw pixel throughput - large primary plane and small cursor plane with 100% overlap, to measure the efficiency of skipping pixels that do not need blending - large primary plane and large cursor plane with only a little overlap (cursor largely off-screen), to measure the efficiency of skipping pixels that do not contribute to the end result at all But that's only curiosity, I think your existing benchmarks sound perfectly fine as the difference is so big. Thanks, pq
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