From: Ralf Baechle <ralf@linux-mips.org>
To: Ronny Meeus <ronny.meeus@gmail.com>
Cc: linux-mips@linux-mips.org
Subject: Re: 2GB userspace limitation in ABI N32
Date: Fri, 12 Oct 2012 12:18:17 +0200 [thread overview]
Message-ID: <20121012101817.GC30020@linux-mips.org> (raw)
In-Reply-To: <CAMJ=MEeSxpcLRCWmkOn7w4Ge1J9Bg7_bFN+Z8xPoYumGFddabA@mail.gmail.com>
On Wed, Oct 10, 2012 at 05:12:16PM +0200, Ronny Meeus wrote:
> Do you have any clue (rough) on the amount of effort this change would cost?
David Daney's reply should give you more information for an estimate.
> About the limited gain we can discuss: if you have a large application
> that has been created assuming 32bit and it needs to be ported to a
> 64bit architecture, I think the effort can be huge and the risk for
> forgetting things is high. It will be very hard to check whether the
> system behaves well under all conditions.
A 64-bit port could start right away without the delay of waiting for
a usable N32-4GB. Added benefit - with N64 you can grow beyond the 3GB.
Downside, due to larger pointers thus better cache locality 32-bit code
generally performs better. And I agree that verification of N32-4GB
probably is easier than for a large application that wasn't written
with the intend of 64-bit support.
In my past as a contractor I've dealth with a few customers who were
trying to avoid going 64-bit at all cost. They had to pay that cost ...
Ralf
prev parent reply other threads:[~2012-10-12 10:18 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-10 6:32 2GB userspace limitation in ABI N32 Ronny Meeus
2012-10-10 8:07 ` Ralf Baechle
2012-10-10 12:57 ` Rich Felker
2012-10-10 16:56 ` David Daney
2012-10-10 17:10 ` Maciej W. Rozycki
2012-10-10 17:34 ` David Daney
2012-10-10 17:49 ` Ronny Meeus
2012-10-10 18:08 ` David Daney
2012-10-10 15:12 ` Ronny Meeus
2012-10-12 10:18 ` Ralf Baechle [this message]
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