TL;DR Screen Optimizations Results for Terminal Emulator Pyte

July 14, 2022

This post describes to some level of detail all the performance boosts and speedups due the optimizations contributed to pyte and summarized here

For large geometries (240x800, 2400x8000), Screen.display runs orders of magnitud faster and consumes between 1.10 and 50.0 times less memory.

For smaller geometries the minimum improvement was of 2 times faster.

Stream.feed is now between 1.10 and 7.30 times faster and if Screen is tuned, the speedup is between 1.14 and 12.0.

For memory usage, Stream.feed is between 1.10 and 17.0 times lighter and up to 44.0 times lighter if Screen is tuned.

Screen.reset is between 1.10 and 1.50 slower but several cases improve if the Screen is tuned (but not all).

However there are a few regressions, most of them small but some up to 4 times.

At the moment of writing this post, the PR is still pending to review.

What is this PR about?

Optimization. My goal was to make pyte faster and lighter specially for large geometries (think in a screen of 240x800 or 2400x8000 size).

Context (background)

While pyte implements a sparse buffer, most of its algorithms are not aware and they don’t take advantage of that making the terminal emulation really slow and consuming a lot of memory.

Contributions

• Upgrade pyperf
• Extended the benchmark tests to test Screen.display, Screen.resize and Screen.reset under different geometries (24x80, 240x800, 2400x8000, 24x8000, 2400x80). With these the benchmark takes much more time (sorry!) but it gives a deeper view of how pyte works.
• Fixed a bug in the benchmarks that used Stream instead of ByteStream. The use of the former led to an incorrect interpretation of the new lines; the use of ByteStream fixed that and it is aligned with the test_input_output.py tests.
• Optimize Screen.display to work (approx) linearly with the input and not with the size of the screen (quadratic). Improved by a lot both for runtime and memory (specially for large geometries).
• Implement Screen.compressed_display that works similar to Screen.display but it allows to “strip” empty space from the left or right and “filter” empty lines on top and bottom of the screen reducing time and memory.
• Optimize Screen.draw with caching of attributes and methods (the same optimizations already present in Stream._parser_fsm).
• Refactor out Char’s foreground, bold, blink (…) into a separated namedtuple CharStyle. When possible, reuse the same style for multiple characters reducing the memory usage at the expense of an additional lookup (instead of char.fg you have char.style.fg).
• Make Char a mutable object allowing changes in the data and width fields to be in-place instead of creating a new Char object.
• Sparse-aware algorithms for Screen.index and Screen.reverse_index that improved indirectly Screen.draw and Stream.feed.
• Sparse-aware algorithms for Screen.resize
• Sparse-aware algorithms for Screen.tabstop
• Sparse-aware algorithms for ScreenHistory.prev_page and ScreenHistory.next_page.
• Sparse-aware algorithms for Screen.insert_characters, Screen.delete_characters, Screen.insert_lines and Screen.delete_characters that improved the performance of “terminal aware” programs.
• Statistics about Screen’s buffer and lines to have insight about the sparsity and usage of these elements. (The API is not not standard like DebugScreen).
• Make the public attribute Screen.buffer return a BufferView. Retrieve of lines from it yield LineView instead of Line objects. This adds an overhead on user code but allows a separation between the public part and the internals. Iterate over LineView still yields Char objects as usual (to much high penalty otherwise).
• Make the public Screen.history’s top and bottom queues return LineView and not Line objects
• Make the private attribute Screen._buffer a dict and not a defaultdict. This prevent adding entries unintentionally that would make the buffer less sparse and therefore slow.
• If the current cursor attributes (style) matches the default attributes of the screen, do not write explicit spaces on erase methods (Screen.erase_characters, Screen.erase_in_line and Screen.erase_in_display)
• When disable_display_graphic is True prevent Screen.select_graphic_rendition to change the cursor attributes (style). If the cursor attrs don’t change, we can optimize the erase methods. The flag is False by default. but just remove the chars from the buffer. This makes speedup other algorithms and maintain high the sparsity (and consume less memory).
• When track_dirty_lines is False use a NullSet for Screen.dirty attribute to not consume any memory and discard any element, disabling effectively the dirty functionality. This saves time and memory for large geometries. The flag is True by default.
• Make Screen.margin always a Margin object so we can avoid checking if it is None or not.

Compatibility changes

The following are changes in the API that may break user code. A special care was taken to avoid this situation.

• Char is not longer a namedtuple so things like _replace are gone. If necessary we could reimplement the API of namedtuple but I don’t think users will use.
• Char is mutable but the user must not relay on this: changes to character will have undefined behaviour. The user must use always the API provided by Screen.
• Char not longer has attributes for fg, bg, bold. Instead, it has a single read-only CharStyle. The Char class implements fg, bg, bold as properties to do the lookup to the style behind the scene. User code should not break then.
• Screen.buffer now is a property that returns a BufferView with a similar API to a dictionary. It yields LineView objects instead of Line objects. These in turn yield Char objects (not views). User can still iterate over the lines and chars as if the buffer were a dense array and not a sparse array as it is really. Like any view, these are valid until the next modification of the screen. This change may break user code if it uses buffer in another way.
• The queues top and bottom of ScreenHistory.history contain LineView and not Line objects. This may break user code.
• Screen.margin is always a Margin object: the None value is not longer supported.

Results

High level results

For large geometries (240x800, 2400x8000), Screen.display runs orders of magnitud faster and consumes between 1.10 and 50.0 times less memory.

For smaller geometries the minimum improvement was of 2 times faster.

Stream.feed is now between 1.10 and 7.30 times faster and if Screen is tuned, the speedup is between 1.14 and 12.0.

However there is a regression for the mc.input test of up to 4 times slower.

For memory usage, Stream.feed is between 1.10 and 17.0 times lighter and up to 44.0 times lighter if Screen is tuned.

Screen.reset is between 1.10 and 1.50 slower but several cases improve if the Screen is tuned (but not all).

TL;DR - Numbers overview

The following is a overview of the numbers got. To make this post as short as possible, the some results were omitted (rows omitted are marked with :::).

Full benchmark results are listed below; people is encouraged to do their own benchmarks for cross validation.

• 0.8.1 - runtime
• 0.8.1 - tracemalloc
• optimized (default) - runtime
• optimized (default) - tracemalloc
• optimized (tuned) - runtime
• optimized (tuned) - tracemalloc

Screen.display

Screen.display was optimized to generate large chunks of spaces very quickly.

For large geometries, this has an huge impact on the performance:

+----------------------------------------------------------+----------+-----------------------------------------+
| Benchmark                                                | 0.8.1    | 0.8.1+screen-optimizations+default-conf |
+==========================================================+==========+=========================================+
| [screen_display 2400x8000] mc.input->Screen              | 6.69 sec | 9.95 us: 672459.98x faster              |
| [screen_display 2400x8000] mc.input->HistoryScreen       | 6.60 sec | 10.3 us: 638209.07x faster              |
| [screen_display 2400x8000] vi.input->HistoryScreen       | 6.80 sec | 132 us: 51648.56x faster                |
| [screen_display 2400x8000] vi.input->Screen              | 6.60 sec | 130 us: 50691.68x faster                |
    :::                 ::::                                    ::::         :::
| [screen_display 240x800] ls.input->HistoryScreen         | 70.1 ms  | 248 us: 283.21x faster                  |
| [screen_display 240x800] ls.input->Screen                | 69.1 ms  | 244 us: 282.76x faster                  |
| [screen_display 240x800] top.input->Screen               | 68.2 ms  | 249 us: 273.98x faster                  |
| [screen_display 240x800] top.input->HistoryScreen        | 67.3 ms  | 257 us: 261.64x faster                  |
    :::                 ::::                                    ::::         :::
| [screen_display 24x80] find-etc.input->HistoryScreen     | 670 us   | 101 us: 6.63x faster                    |
| [screen_display 24x80] find-etc.input->Screen            | 640 us   | 97.9 us: 6.54x faster                   |
| [screen_display 24x80] vi.input->HistoryScreen           | 606 us   | 115 us: 5.27x faster                    |
| [screen_display 24x80] vi.input->Screen                  | 584 us   | 117 us: 5.00x faster                    |
| [screen_display 24x80] cat-gpl3.input->Screen            | 605 us   | 189 us: 3.21x faster                    |
| [screen_display 24x80] cat-gpl3.input->HistoryScreen     | 605 us   | 195 us: 3.11x faster                    |
| [screen_display 24x80] ls.input->HistoryScreen           | 609 us   | 221 us: 2.75x faster                    |
| [screen_display 24x80] ls.input->Screen                  | 585 us   | 221 us: 2.65x faster                    |
| [screen_display 24x80] top.input->Screen                 | 567 us   | 244 us: 2.33x faster                    |
| [screen_display 24x80] top.input->HistoryScreen          | 580 us   | 251 us: 2.32x faster                    |
| [screen_display 24x80] htop.input->HistoryScreen         | 564 us   | 269 us: 2.10x faster                    |
| [screen_display 24x80] htop.input->Screen                | 559 us   | 273 us: 2.05x faster                    |

Screen.display takes advantage of the sparsity of the screen and therefore it was indirectly beneficed by the optimizations done across Screen to avoid filling it with false entries.

Screen.display it was also optimized on memory (tracemalloc) avoiding then append of each space character separately when they could be appended in a single chunk.

+--------------------------------------------------------------+-------------------+-----------------------------------------------------+
| Benchmark                                                    | 0.8.1.tracemalloc | 0.8.1+screen-optimizations+default-conf.tracemalloc |
+==============================================================+===================+=====================================================+
| [screen_display 2400x8000] ls.input->HistoryScreen           | 19.7 MB           | 408.1 kB: 49.43x faster                             |
| [screen_display 2400x8000] mc.input->HistoryScreen           | 19.7 MB           | 411.4 kB: 49.04x faster                             |
| [screen_display 2400x8000] mc.input->Screen                  | 19.7 MB           | 411.4 kB: 49.04x faster                             |
| [screen_display 2400x8000] ls.input->Screen                  | 19.7 MB           | 411.5 kB: 49.03x faster                             |
| [screen_display 2400x8000] vi.input->HistoryScreen           | 18.5 MB           | 404.7 kB: 46.84x faster                             |
| [screen_display 2400x8000] top.input->HistoryScreen          | 18.5 MB           | 408.3 kB: 46.43x faster                             |
| [screen_display 2400x8000] vi.input->Screen                  | 18.5 MB           | 408.5 kB: 46.40x faster                             |
| [screen_display 2400x8000] top.input->Screen                 | 18.5 MB           | 411.5 kB: 46.07x faster                             |
| [screen_display 2400x8000] htop.input->Screen                | 18.5 MB           | 1102.6 kB: 17.19x faster                            |
| [screen_display 2400x8000] htop.input->HistoryScreen         | 18.5 MB           | 1103.2 kB: 17.18x faster                            |
| [screen_display 2400x8000] cat-gpl3.input->HistoryScreen     | 19.5 MB           | 5392.6 kB: 3.70x faster                             |
| [screen_display 2400x8000] cat-gpl3.input->Screen            | 19.5 MB           | 5392.0 kB: 3.70x faster                             |
| [screen_display 240x800] mc.input->Screen                    | 513.2 kB          | 403.5 kB: 1.27x faster                              |
| [screen_display 240x800] ls.input->Screen                    | 517.0 kB          | 411.5 kB: 1.26x faster                              |
| [screen_display 240x800] ls.input->HistoryScreen             | 511.7 kB          | 408.1 kB: 1.25x faster                              |
| [screen_display 240x800] mc.input->HistoryScreen             | 510.4 kB          | 411.4 kB: 1.24x faster                              |
| [screen_display 2400x8000] find-etc.input->HistoryScreen     | 18.7 MB           | 16.6 MB: 1.12x faster                               |
| [screen_display 2400x8000] find-etc.input->Screen            | 18.7 MB           | 16.6 MB: 1.12x faster                               |

The only two regressions are:

| [screen_display 240x800] htop.input->HistoryScreen           | 408.7 kB          | 487.3 kB: 1.19x slower                              |
| [screen_display 240x800] htop.input->Screen                  | 405.8 kB          | 486.2 kB: 1.20x slower                              |

Not sure why this happen.

Stream.feed

stream.feed was not modified but its runtime depends on Screen’s performance.

For terminal programs that just write into then terminal, like cat-gpl3 and find-etc, stream.feed merely sends then input to Screen.draw for rendering.

The method Screen.draw was optimized to avoid the modification of the cursor internally and update it only at the exit. This saved a few lookups.

While not been frequently called, Screen.index was the next bottleneck for Screen.draw: it moves all the lines of the screen that it means that all the entries of the buffer are rewritten.

Screen.index and Screen.reverse_index were optimized to take advantage of the sparsity and to avoid adding false entries.

This resulted on a speedup across the tests:

+----------------------------------------------------------+----------+-----------------------------------------+
| Benchmark                                                | 0.8.1    | 0.8.1+screen-optimizations+default-conf |
+==========================================================+==========+=========================================+
| [stream_feed 2400x8000] vi.input->HistoryScreen          | 49.4 ms  | 6.70 ms: 7.38x faster                   |
| [stream_feed 2400x8000] top.input->HistoryScreen         | 7.35 ms  | 1.31 ms: 5.62x faster                   |
| [stream_feed 2400x8000] find-etc.input->HistoryScreen    | 2.92 sec | 543 ms: 5.38x faster                    |
| [stream_feed 240x800] ls.input->HistoryScreen            | 9.29 ms  | 1.75 ms: 5.31x faster                   |
| [stream_feed 24x80] top.input->HistoryScreen             | 6.61 ms  | 1.25 ms: 5.30x faster                   |
| [stream_feed 240x800] top.input->HistoryScreen           | 6.57 ms  | 1.24 ms: 5.29x faster                   |
| [stream_feed 240x800] cat-gpl3.input->HistoryScreen      | 215 ms   | 43.3 ms: 4.97x faster                   |
| [stream_feed 24x80] ls.input->HistoryScreen              | 6.26 ms  | 1.34 ms: 4.68x faster                   |
| [stream_feed 24x80] cat-gpl3.input->HistoryScreen        | 140 ms   | 31.9 ms: 4.38x faster                   |
| [stream_feed 240x800] find-etc.input->HistoryScreen      | 532 ms   | 123 ms: 4.32x faster                    |
| [stream_feed 2400x8000] vi.input->Screen                 | 13.7 ms  | 3.53 ms: 3.88x faster                   |
| [stream_feed 24x80] find-etc.input->HistoryScreen        | 294 ms   | 81.1 ms: 3.62x faster                   |
| [stream_feed 2400x8000] htop.input->HistoryScreen        | 122 ms   | 34.4 ms: 3.54x faster                   |
    :::                 ::::                                    ::::         :::
| [stream_feed 240x800] vi.input->Screen                   | 5.39 ms  | 2.67 ms: 2.02x faster                   |
| [stream_feed 24x80] mc.input->HistoryScreen              | 44.3 ms  | 24.4 ms: 1.82x faster                   |
| [stream_feed 2400x8000] htop.input->Screen               | 38.1 ms  | 21.4 ms: 1.78x faster                   |
| [stream_feed 240x800] htop.input->Screen                 | 23.2 ms  | 13.2 ms: 1.76x faster                   |
| [stream_feed 240x800] find-etc.input->Screen             | 134 ms   | 77.0 ms: 1.74x faster                   |
| [stream_feed 24x80] vi.input->Screen                     | 4.45 ms  | 2.57 ms: 1.73x faster                   |
| [stream_feed 24x80] htop.input->Screen                   | 20.8 ms  | 12.2 ms: 1.71x faster                   |
| [stream_feed 2400x8000] cat-gpl3.input->HistoryScreen    | 262 ms   | 157 ms: 1.67x faster                    |
| [stream_feed 240x800] mc.input->HistoryScreen            | 63.7 ms  | 43.8 ms: 1.45x faster                   |
| [stream_feed 2400x8000] ls.input->Screen                 | 7.77 ms  | 5.61 ms: 1.38x faster                   |
| [stream_feed 24x80] mc.input->Screen                     | 17.6 ms  | 13.1 ms: 1.34x faster                   |
| [stream_feed 2400x8000] find-etc.input->Screen           | 616 ms   | 501 ms: 1.23x faster                    |
| [stream_feed 2400x8000] cat-gpl3.input->Screen           | 170 ms   | 143 ms: 1.19x faster                    |
| [stream_feed 2400x8000] mc.input->HistoryScreen          | 259 ms   | 285 ms: 1.10x slower                    |
| [stream_feed 240x800] mc.input->Screen                   | 23.3 ms  | 32.3 ms: 1.39x slower                   |
| [stream_feed 2400x8000] mc.input->Screen                 | 71.2 ms  | 281 ms: 3.94x slower                    |

The mc.input however took much more time.

When track_dirty_lines is False and disable_display_graphic is True, the overall performance increases even further.

+----------------------------------------------------------+----------+----------------------------------------+
| Benchmark                                                | 0.8.1    | 0.8.1+screen-optimizations+custom-conf |
+==========================================================+==========+========================================+
| [stream_feed 2400x8000] mc.input->HistoryScreen          | 259 ms   | 21.2 ms: 12.19x faster                 |
| [stream_feed 2400x8000] vi.input->HistoryScreen          | 49.4 ms  | 5.52 ms: 8.95x faster                  |
| [stream_feed 2400x8000] mc.input->Screen                 | 71.2 ms  | 10.8 ms: 6.60x faster                  |
| [stream_feed 2400x8000] find-etc.input->HistoryScreen    | 2.92 sec | 464 ms: 6.29x faster                   |
| [stream_feed 2400x8000] top.input->HistoryScreen         | 7.35 ms  | 1.27 ms: 5.80x faster                  |
| [stream_feed 2400x8000] htop.input->HistoryScreen        | 122 ms   | 22.3 ms: 5.45x faster                  |
| [stream_feed 2400x8000] vi.input->Screen                 | 13.7 ms  | 2.52 ms: 5.43x faster                  |
| [stream_feed 24x80] top.input->HistoryScreen             | 6.61 ms  | 1.23 ms: 5.38x faster                  |
| [stream_feed 240x800] ls.input->HistoryScreen            | 9.29 ms  | 1.73 ms: 5.37x faster                  |
| [stream_feed 240x800] cat-gpl3.input->HistoryScreen      | 215 ms   | 42.0 ms: 5.12x faster                  |
    :::                 ::::                                    ::::         :::
| [stream_feed 24x80] cat-gpl3.input->Screen               | 46.3 ms  | 17.2 ms: 2.69x faster                  |
| [stream_feed 240x800] top.input->Screen                  | 2.39 ms  | 913 us: 2.61x faster                   |
| [stream_feed 24x80] top.input->Screen                    | 2.36 ms  | 914 us: 2.58x faster                   |
| [stream_feed 2400x8000] ls.input->HistoryScreen          | 13.4 ms  | 5.39 ms: 2.50x faster                  |
| [stream_feed 24x80] htop.input->HistoryScreen            | 55.3 ms  | 22.6 ms: 2.44x faster                  |
    :::                 ::::                                    ::::         :::
| [stream_feed 240x800] vi.input->Screen                   | 5.39 ms  | 2.57 ms: 2.10x faster                  |
| [stream_feed 24x80] mc.input->HistoryScreen              | 44.3 ms  | 21.3 ms: 2.08x faster                  |
| [stream_feed 2400x8000] cat-gpl3.input->HistoryScreen    | 262 ms   | 132 ms: 1.99x faster                   |
| [stream_feed 240x800] find-etc.input->Screen             | 134 ms   | 76.3 ms: 1.76x faster                  |
| [stream_feed 24x80] vi.input->Screen                     | 4.45 ms  | 2.54 ms: 1.75x faster                  |
| [stream_feed 24x80] mc.input->Screen                     | 17.6 ms  | 10.6 ms: 1.66x faster                  |
| [stream_feed 2400x8000] ls.input->Screen                 | 7.77 ms  | 4.85 ms: 1.60x faster                  |
| [stream_feed 2400x8000] find-etc.input->Screen           | 616 ms   | 422 ms: 1.46x faster                   |
| [stream_feed 2400x8000] cat-gpl3.input->Screen           | 170 ms   | 118 ms: 1.44x faster                   |

On memory there is an improvement too:

+--------------------------------------------------------------+-------------------+-----------------------------------------------------+
| Benchmark                                                    | 0.8.1.tracemalloc | 0.8.1+screen-optimizations+default-conf.tracemalloc |
+==============================================================+===================+=====================================================+
| [stream_feed 2400x8000] vi.input->HistoryScreen              | 11.7 MB           | 686.8 kB: 17.45x faster                             |
| [stream_feed 2400x8000] vi.input->Screen                     | 4742.1 kB         | 538.0 kB: 8.81x faster                              |
| [stream_feed 2400x8000] htop.input->HistoryScreen            | 14.5 MB           | 3552.1 kB: 4.18x faster                             |
| [stream_feed 240x800] vi.input->HistoryScreen                | 2679.0 kB         | 686.8 kB: 3.90x faster                              |
| [stream_feed 2400x8000] top.input->HistoryScreen             | 2120.7 kB         | 611.8 kB: 3.47x faster                              |
| [stream_feed 2400x8000] htop.input->Screen                   | 11.5 MB           | 3408.2 kB: 3.45x faster                             |
| [stream_feed 2400x8000] top.input->Screen                    | 2155.1 kB         | 680.2 kB: 3.17x faster                              |
| [stream_feed 240x800] htop.input->HistoryScreen              | 2189.7 kB         | 1005.8 kB: 2.18x faster                             |
| [stream_feed 240x800] vi.input->Screen                       | 1107.7 kB         | 536.1 kB: 2.07x faster                              |
| [stream_feed 240x800] htop.input->Screen                     | 1782.7 kB         | 990.6 kB: 1.80x faster                              |
            :::                 ::::                                    ::::         :::
| [stream_feed 240x800] find-etc.input->HistoryScreen          | 2233.5 kB         | 1502.4 kB: 1.49x faster                             |
| [stream_feed 24x80] ls.input->HistoryScreen                  | 1554.3 kB         | 1086.0 kB: 1.43x faster                             |
| [stream_feed 24x80] cat-gpl3.input->HistoryScreen            | 1354.0 kB         | 960.1 kB: 1.41x faster                              |
| [stream_feed 24x80] top.input->Screen                        | 948.2 kB          | 680.2 kB: 1.39x faster                              |
| [stream_feed 24x80] vi.input->HistoryScreen                  | 954.7 kB          | 686.8 kB: 1.39x faster                              |
| [stream_feed 24x80] find-etc.input->HistoryScreen            | 1017.6 kB         | 774.9 kB: 1.31x faster                              |
| [stream_feed 240x800] top.input->HistoryScreen               | 763.6 kB          | 653.6 kB: 1.17x faster                              |
| [stream_feed 24x80] mc.input->HistoryScreen                  | 485.0 kB          | 417.6 kB: 1.16x faster                              |
| [stream_feed 24x80] htop.input->Screen                       | 936.1 kB          | 814.3 kB: 1.15x faster                              |
| [stream_feed 24x80] mc.input->Screen                         | 722.3 kB          | 651.6 kB: 1.11x faster                              |

The following are the tests that show regression on memory usage.

| [stream_feed 240x800] mc.input->Screen                       | 1842.2 kB         | 2577.4 kB: 1.40x slower                             |
| [stream_feed 240x800] mc.input->HistoryScreen                | 1793.2 kB         | 2548.1 kB: 1.42x slower                             |
| [stream_feed 2400x8000] mc.input->HistoryScreen              | 13.6 MB           | 22.3 MB: 1.64x slower                               |
| [stream_feed 2400x8000] ls.input->HistoryScreen              | 8422.1 kB         | 13.7 MB: 1.67x slower                               |
| [stream_feed 2400x8000] mc.input->Screen                     | 12.2 MB           | 22.3 MB: 1.82x slower                               |

When track_dirty_lines is False and disable_display_graphic is True, this is even better:

+--------------------------------------------------------------+-------------------+----------------------------------------------------+
| Benchmark                                                    | 0.8.1.tracemalloc | 0.8.1+screen-optimizations+custom-conf.tracemalloc |
+==============================================================+===================+====================================================+
| [stream_feed 2400x8000] mc.input->HistoryScreen              | 13.6 MB           | 414.1 kB: 33.60x faster                            |
| [stream_feed 2400x8000] mc.input->Screen                     | 12.2 MB           | 447.6 kB: 27.98x faster                            |
| [stream_feed 2400x8000] htop.input->Screen                   | 11.5 MB           | 600.5 kB: 19.59x faster                            |
| [stream_feed 2400x8000] vi.input->HistoryScreen              | 11.7 MB           | 665.4 kB: 18.01x faster                            |
| [stream_feed 2400x8000] htop.input->HistoryScreen            | 14.5 MB           | 1009.0 kB: 14.73x faster                           |
| [stream_feed 2400x8000] vi.input->Screen                     | 4742.1 kB         | 522.4 kB: 9.08x faster                             |
| [stream_feed 240x800] mc.input->HistoryScreen                | 1793.2 kB         | 417.4 kB: 4.30x faster                             |
| [stream_feed 240x800] mc.input->Screen                       | 1842.2 kB         | 447.6 kB: 4.12x faster                             |
| [stream_feed 240x800] vi.input->HistoryScreen                | 2679.0 kB         | 652.6 kB: 4.11x faster                             |
| [stream_feed 2400x8000] top.input->HistoryScreen             | 2120.7 kB         | 653.6 kB: 3.24x faster                             |
| [stream_feed 2400x8000] top.input->Screen                    | 2155.1 kB         | 680.6 kB: 3.17x faster                             |
| [stream_feed 240x800] htop.input->Screen                     | 1782.7 kB         | 600.5 kB: 2.97x faster                             |
| [stream_feed 240x800] htop.input->HistoryScreen              | 2189.7 kB         | 785.0 kB: 2.79x faster                             |
| [stream_feed 240x800] vi.input->Screen                       | 1107.7 kB         | 522.4 kB: 2.12x faster                             |
| [stream_feed 2400x8000] cat-gpl3.input->HistoryScreen        | 20.3 MB           | 11.8 MB: 1.72x faster                              |
            :::                 ::::                                    ::::         :::
| [stream_feed 24x80] find-etc.input->HistoryScreen            | 1017.6 kB         | 774.8 kB: 1.31x faster                             |
| [stream_feed 240x800] top.input->HistoryScreen               | 763.6 kB          | 653.6 kB: 1.17x faster                             |
| [stream_feed 24x80] mc.input->HistoryScreen                  | 485.0 kB          | 422.0 kB: 1.15x faster                             |

However, we still have some regressions:

| [stream_feed 24x80] htop.input->HistoryScreen                | 863.7 kB          | 1009.0 kB: 1.17x slower                            |
| [stream_feed 2400x8000] ls.input->HistoryScreen              | 8422.1 kB         | 13.7 MB: 1.67x slower                              |

Screen.reset

For Screen.reset we have a regressions, some minor, some not-so-much minor:

+----------------------------------------------------------+----------+-----------------------------------------+
| Benchmark                                                | 0.8.1    | 0.8.1+screen-optimizations+default-conf |
+==========================================================+==========+=========================================+
| [screen_reset 2400x8000] ls.input->HistoryScreen         | 65.4 us  | 68.9 us: 1.05x slower                   |
| [screen_reset 2400x8000] mc.input->Screen                | 51.9 us  | 54.8 us: 1.06x slower                   |
| [screen_reset 2400x8000] top.input->HistoryScreen        | 65.6 us  | 69.5 us: 1.06x slower                   |
    :::                 ::::                                    ::::         :::
| [screen_reset 24x80] cat-gpl3.input->HistoryScreen       | 13.2 us  | 15.4 us: 1.17x slower                   |
| [screen_reset 24x80] vi.input->HistoryScreen             | 13.0 us  | 15.3 us: 1.18x slower                   |
| [screen_reset 240x800] htop.input->Screen                | 4.87 us  | 5.78 us: 1.19x slower                   |
| [screen_reset 24x80] mc.input->HistoryScreen             | 13.1 us  | 15.7 us: 1.19x slower                   |
| [screen_reset 240x800] mc.input->Screen                  | 4.81 us  | 5.75 us: 1.20x slower                   |
| [screen_reset 24x80] ls.input->HistoryScreen             | 13.0 us  | 15.5 us: 1.20x slower                   |
| [screen_reset 24x80] find-etc.input->HistoryScreen       | 13.0 us  | 15.6 us: 1.20x slower                   |
| [screen_reset 24x80] htop.input->HistoryScreen           | 12.9 us  | 15.5 us: 1.21x slower                   |
| [screen_reset 240x800] find-etc.input->Screen            | 4.86 us  | 5.87 us: 1.21x slower                   |
| [screen_reset 240x800] htop.input->HistoryScreen         | 15.6 us  | 18.9 us: 1.21x slower                   |
| [screen_reset 240x800] vi.input->Screen                  | 4.83 us  | 5.87 us: 1.22x slower                   |
| [screen_reset 240x800] top.input->Screen                 | 4.72 us  | 5.77 us: 1.22x slower                   |
    :::                 ::::                                    ::::         :::
| [screen_reset 240x800] ls.input->Screen                  | 4.79 us  | 5.86 us: 1.22x slower                   |
| [screen_reset 240x800] cat-gpl3.input->Screen            | 4.79 us  | 5.89 us: 1.23x slower                   |
| [screen_reset 24x80] vi.input->Screen                    | 2.05 us  | 3.05 us: 1.49x slower                   |
| [screen_reset 24x80] mc.input->Screen                    | 2.04 us  | 3.05 us: 1.49x slower                   |
| [screen_reset 24x80] ls.input->Screen                    | 2.01 us  | 3.01 us: 1.50x slower                   |
| [screen_reset 24x80] htop.input->Screen                  | 2.02 us  | 3.06 us: 1.51x slower                   |
| [screen_reset 24x80] cat-gpl3.input->Screen              | 2.03 us  | 3.07 us: 1.52x slower                   |
| [screen_reset 24x80] top.input->Screen                   | 2.03 us  | 3.11 us: 1.53x slower                   |
| [screen_reset 24x80] find-etc.input->Screen              | 2.00 us  | 3.06 us: 1.53x slower                   |

However when track_dirty_lines is False and disable_display_graphic is True, the things improves (but we still have regressions):

+----------------------------------------------------------+----------+----------------------------------------+
| Benchmark                                                | 0.8.1    | 0.8.1+screen-optimizations+custom-conf |
+==========================================================+==========+========================================+
| [screen_reset 2400x8000] find-etc.input->Screen          | 51.3 us  | 15.2 us: 3.38x faster                  |
| [screen_reset 2400x8000] mc.input->Screen                | 51.9 us  | 15.5 us: 3.35x faster                  |
| [screen_reset 2400x8000] vi.input->Screen                | 52.8 us  | 15.9 us: 3.32x faster                  |
    :::                 ::::                                    ::::         :::
| [screen_reset 2400x8000] cat-gpl3.input->HistoryScreen   | 66.5 us  | 29.9 us: 2.22x faster                  |
| [screen_reset 2400x8000] htop.input->HistoryScreen       | 64.6 us  | 29.4 us: 2.20x faster                  |
| [screen_reset 240x800] htop.input->Screen                | 4.87 us  | 4.58 us: 1.06x faster                  |
| [screen_reset 240x800] find-etc.input->Screen            | 4.86 us  | 4.62 us: 1.05x faster                  |
| [screen_reset 240x800] cat-gpl3.input->HistoryScreen     | 16.0 us  | 17.0 us: 1.06x slower                  |
| [screen_reset 240x800] mc.input->HistoryScreen           | 16.0 us  | 17.1 us: 1.07x slower                  |
| [screen_reset 240x800] find-etc.input->HistoryScreen     | 16.1 us  | 17.3 us: 1.07x slower                  |
| [screen_reset 240x800] top.input->HistoryScreen          | 15.9 us  | 17.1 us: 1.08x slower                  |
| [screen_reset 240x800] htop.input->HistoryScreen         | 15.6 us  | 17.5 us: 1.12x slower                  |
    :::                 ::::                                    ::::         :::
| [screen_reset 24x80] htop.input->HistoryScreen           | 12.9 us  | 15.3 us: 1.19x slower                  |
| [screen_reset 24x80] htop.input->Screen                  | 2.02 us  | 2.89 us: 1.43x slower                  |
| [screen_reset 24x80] top.input->Screen                   | 2.03 us  | 2.92 us: 1.44x slower                  |
| [screen_reset 24x80] mc.input->Screen                    | 2.04 us  | 2.94 us: 1.44x slower                  |
| [screen_reset 24x80] ls.input->Screen                    | 2.01 us  | 2.90 us: 1.44x slower                  |
| [screen_reset 24x80] vi.input->Screen                    | 2.05 us  | 2.96 us: 1.44x slower                  |
| [screen_reset 24x80] find-etc.input->Screen              | 2.00 us  | 2.90 us: 1.45x slower                  |
| [screen_reset 24x80] cat-gpl3.input->Screen              | 2.03 us  | 2.96 us: 1.46x slower                  |

Related tags: python, pyte, byexample, optimization, performance, tldr, tl;dr