Re: pthread_create() slow for many threads; also time to revisit64b context switch optimization?

[Ulrich Drepper]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Jamie Lokier wrote:
> Suggest:
> 
> +#define MAP_STACK       0x20000         /* 31bit or 64bit address for stack, */
> +                                        /* whichever is faster on this CPU */

I agree.  Except for the comment.


> Also, is this _only_ useful for thread stacks, or are there other
> memory allocations where 31-bitness affects execution speed on old P4s?

Actually, I would define the flag as "do whatever is best assuming the
allocation is used for stacks".

For instance, minimally the /proc/*/maps output could show "[user
stack]" or something like this.  For security, perhaps, setting of
PROC_EXEC can be prevented.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (GNU/Linux)
Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org

iEYEARECAAYFAkiluUMACgkQ2ijCOnn/RHSb5gCfb5VhiLA/wbamoAVqfxR32k4N
tSIAoK/KAmwcVd+RjkPnb9RSuAeL/KLV
=2ynl
-----END PGP SIGNATURE-----
--
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/