Re: Crashes in "C-h h"

[Eli Zaretskii]

> Cc: address@hidden, address@hidden
> From: Paul Eggert <address@hidden>
> Date: Thu, 4 Jul 2019 00:15:12 -0700
> 
> 1030-lnxsrv09 $ time ./a.out 0 0
> 
> real  0m51.933s
> user  0m51.927s
> sys   0m0.001s
> 1031-lnxsrv09 $ time ./a.out 0 0 0
> 
> real  2m16.960s
> user  2m16.960s
> sys   0m0.000s
> 1032-lnxsrv09 $ time ./a.out 0 0 0 0
> 
> real  0m59.678s
> user  0m59.677s
> sys   0m0.001s

Thanks.

> This indicates that on this !USE_LSB platform, the EQ+make_fixnum code is 
> about 
> ten times faster than the FIXNUMP+XFIXNUM code on this benchmark.

You mean twice faster (~2m vs ~1m), right?

> I'm not surprised by the performance disparity, as branch-prediction
> failures can be pretty expensive.

Which indeed means that if the object is not guaranteed to be a
fixnum, using XFIXNUM is generally suboptimal.