One of the potential projects to improve pageload revolves around the idea to make the baseline jit able to compile code at a lower granularity. In order to estimate the potential win here it's valuable to understand the size of the scripts we're generally compiling. I've measured this on CNN, New York Times and, for reference, Speedometer, here are the results, the left column is the size of the script in jsbytecode, the right side is the amount of compilations of scripts in that bucket: PS C:\Users\Bas\Dev> .\ProcessCompiling.ps1 .\CNNCompiling.txt Name Value ---- ----- 1 - 2 20 2 - 4 10 4 - 8 108 8 - 16 133 16 - 32 545 32 - 64 751 64 - 128 741 128 - 256 823 256 - 512 442 512 - 1024 212 1024 - 2048 76 2048 - 4096 21 4096 - 8192 3 8192 - 16384 3 16384 - 32768 1 32768 - 65536 1 65536 - 131072 1 PS C:\Users\Bas\Dev> .\ProcessCompiling.ps1 .\NYTCompiling.txt Name Value ---- ----- 1 - 2 23 2 - 4 7 4 - 8 89 8 - 16 155 16 - 32 584 32 - 64 784 64 - 128 791 128 - 256 730 256 - 512 436 512 - 1024 162 1024 - 2048 37 2048 - 4096 16 4096 - 8192 6 8192 - 16384 2 16384 - 32768 1 PS C:\Users\Bas\Dev> .\ProcessCompiling.ps1 .\SpeedometerCompiling.txt Name Value ---- ----- 1 - 2 297 2 - 4 105 4 - 8 624 8 - 16 964 16 - 32 6207 32 - 64 9261 64 - 128 10628 128 - 256 9951 256 - 512 8003 512 - 1024 3146 1024 - 2048 728 2048 - 4096 121

My interpretation of these numbers is as follows. The vast bulk of BL-compiled scripts are small individually, but the volume is high. In the page-load examples (not speedometer), the "central mass" accounts for at least 500k of bytecode that is compiled, and additionally each individual compile will contribute one or more mprotects towards the cost. When :jandem's new compiled interpreter lands, and we are able to push out baseline compilation until a later point in time, this volume should reduce significantly, and we should re-measure and evaluate the remaining impact.

(In reply to Kannan Vijayan [:djvj] from comment #1) > When :jandem's new compiled interpreter lands, and we are able to push out > baseline compilation until a later point in time, this volume should reduce > significantly, and we should re-measure and evaluate the remaining impact. Yeah I wanted to suggest waiting for that before spending too much time on it, because we'll likely need to do it again in a few months.