Re: [PATCH v4 RESEND] x86/asm/entry/32, selftests: Add 'test_syscall_vdso' test

[Ingo Molnar]

* Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:

> > (I'm not very comfortable about additional six push/pops
> > which are necessary for this to happen. I'm surprised
> > maintainers tentatively agreed to that -
> > I was grilled and asked to prove with measurements
> > that *one* additional push+pop wasn't adding significant overhead).
> 
> I suspect that I need to make the series faster.
> 
> Also, int $0x80 isn't a fast path for any legitimate use case except
> Debian, and I would argue that Debian is just buggy.

So buggy in the sense of not making use of faster syscalls, right? It won't break 
in any visible way, correct?

So if this heavy int80 syscall use happens even with the latest version of Debian 
as well then it would be nice to figure out what's wrong there, and provide an 
optimization patch to their libc guys or so - to make sure we fully understand the 
problem.

Thanks,

	Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/