On Tue, 10 Jun 2025, Nathan Bossart wrote:
> So, fseeko() starts winning around 4096 bytes. On macOS, the differences
> aren't quite as dramatic, but 4096 bytes is the break-even point there,
> too. I imagine there's a buffer around that size somewhere...
>
> This doesn't fully explain the results you are seeing, but it does seem to
> validate the idea. I'm curious if you see further improvement with even
> lower thresholds (e.g., 8KB, 16KB, 32KB).
By the way, I might have set the threshold to 1MB in my program, but
lowering it won't show a difference in my test case, since the lseek()s I
was noticing before the patch were mostly 8-16KB forward. Not sure what is
the defining factor for that. Maybe the compression algorithm, or how wide
the table is?
Dimitris
