[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: x86: faster strncpy_from_user()



On Tue, Apr 10, 2012 at 5:43 PM, David Miller <davem@xxxxxxxxxxxxx> wrote:
> From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Date: Tue, 10 Apr 2012 17:34:14 -0700
>
>> Sparc has "faligndata", no?
>
> It's an FPU instruction :-)

Ok.

> The barrel shift would be the fastest on sparc.

.. and you don't have a double shift, right? So you'd need to do two
shifts and the or for each word.

At which point it is probably pointless to even bother on sparc32,
since you only get four bytes per loop. But on 64-bit it presumably
ends up being at least a slight win.

                        Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-arch" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Linux Kernel]     [Kernel Newbies]     [x86 Platform Driver]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Linux FS]     [Photo]     [Yosemite]     [Yosemite Discussion]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Video 4 Linux]     [Device Mapper]     [Linux Resources]


  Powered by Linux