New EC2 instance types

[Martin Pool]

On 9 March 2012 18:17, Clint Byrum <clint at ubuntu.com> wrote:
>
> From the article:
>
> "You can now launch 64-bit operating systems on the Small and Medium
> instance types."
>
> I read that as you will be running a 64-bit kernel and userland, and
> so I would assume that means you would be gaining the reduced syscall
> latency seen in the micro-benchmarks. Whether that leads to real-world
> measurable improvements will of course require more investigation.

The AMD slides have

"Microbenchmarks: Syscalls on compat" comparing "x86-64" to "i686 on
x86-64" (ie 32-bit userland on 64-bit kernel), showing the first is
faster than the second.  But the second of them is not a situation
that is likely to occur on AWS, so the paper doesn't really have
anything to say about syscall latency on AWS, as far as I can see.
The only relevant consequence is you _shouldn't_ use a 64 bit instance
to run a 32 bit binary.

I'm still happy to see this feature and it probably will be faster in
many cases, though like you say ymmv.

-- 
Martin