Hi Richard,
On Mon, Aug 28, 2023 at 2:12 PM Richard <richie...@arcor.de> wrote:
> On August 28, 2023 10:57:25 AM UTC, John Paul Adrian Glaubitz
> <glaub...@physik.fu-berlin.de> wrote:
> >On Sat, 2023-08-26 at 19:24 +0000, Richard wrote:
> >> > Not only mold but also most notably the following projects:
> >>
> >> a linker that is broken by a slightly unusual alignment isn't exactly a
> >> prime example.. if any project I would expect linkers and binary tools
> >> to pay attention to portability.
> >
> >Portable shouldn't mean having to accommodate for unreasonable design
> >decisions
> >of other developers. It's perfectly fine to assume 32-bit natural alignment
> >on
> >a 32-bit platform and I don't think it's fair to put the burden of adopting
> >for
> >unusual design decisions on to upstream projects.
>
> Assuming anything that is not declared by the c standard is not good imho.
> The C lang is well known for its pitfalls and the basic binary tools ought
> not to set bad precedents ignoring those.
>
> It is also reasonable to assume that on modern hw cache is filled in blocks
> of perhaps 1k or more and thus "unnatural" alignment might actually help
> performance because more fits into that one data burst.
"1k" (I assume you mean 1 KiB?) is a bit much...
Note that on several architectures you cannot do unaligned accesses,
so you have to declare such a structure with __attribute__((__packed__)),
and thus not only live with the overhead of doing unaligned accesses
from the D-cache, but also in emulating them in software...
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
