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Linux 3.4 kernel released

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Re: Linux 3.4 kernel released

#11

Post by sparky »

seats wrote: post #7
slug wrote: post #6

Earlier quoted context omitted.

Anyone has a good argument why NOT to use this for every non memory intensive application? I always thought that using 64bit pointers was a waste of memory when not needed and this x32 abi to me seems fantastic since it keeps the several advantages of newer 64bit cpus (more registers for example as mentioned in the article).

If an application is not memory intensive, why would you care if there is 'waste'? Personally I wish everyone would just move to 64 bit all the time.

'not memory intensive' is an ambiguous term. he meant 'does not use a lot of memory, but may access what memory it does use quite a bit'. you meant 'does not access memory often, and performance thus does not depend much on memory access latency'.

Re: Linux 3.4 kernel released

#12

Post by sparky »

slug wrote: post #6
andrewvc wrote: post #3

The X32 ABI is interesting. Who'd have thought this many years after 64 bit becoming mainstream, (and decades after it becoming mainstream on servers) something like this would be needed.

Anyone has a good argument why NOT to use this for every non memory intensive application? I always thought that using 64bit pointers was a waste of memory when not needed and this x32 abi to me seems fantastic since it keeps the several advantages of newer 64bit cpus (more registers for example as mentioned in the article).

seems like a great idea. toolchain support may be an issue for a while, especially if you link against libraries with a different ABI. one thing to keep in mind is that the performance gain from e.g. more registers may not be as big as you'd think, since the hardware already plays lots of tricks to get around i386's limitations (e.g. register renaming) and likely extracts a good bit of the available ILP.

Re: Linux 3.4 kernel released

#14

Post by haberman »

seats wrote: post #7
slug wrote: post #6

Earlier quoted context omitted.

Anyone has a good argument why NOT to use this for every non memory intensive application? I always thought that using 64bit pointers was a waste of memory when not needed and this x32 abi to me seems fantastic since it keeps the several advantages of newer 64bit cpus (more registers for example as mentioned in the article).

If an application is not memory intensive, why would you care if there is 'waste'? Personally I wish everyone would just move to 64 bit all the time.

> If an application is not memory intensive, why would you care if there is 'waste'?

Performance. What other reason do you need? (Using cache more efficiently makes programs run faster).

Re: Linux 3.4 kernel released

#15

Post by haberman »

andrewvc wrote: post #3

The X32 ABI is interesting. Who'd have thought this many years after 64 bit becoming mainstream, (and decades after it becoming mainstream on servers) something like this would be needed.

> Who'd have thought [...]

Well, Donald Knuth for one. Here's a blog entry I wrote about Donald Knuth and how he asked for this a while back. I think it makes a lot of sense and I'm really glad to see this maturing!

http://blog.reverberate.org/2011/09/making-knuth-wish-come-t...

Re: Linux 3.4 kernel released

#16

Post by javert »

thornofmight wrote: post #8
christianbryant wrote: post #5

What I thought was more interesting (Linus noted "Nothing really exciting happened since -rc7...") was the exchange between Linus and Peter Zijlstra, in particular this Linus eruption: https://lkml.org/lkml/2012/5/19/97

Your link is empty.

Works for me.

Re: Linux 3.4 kernel released

#18

Post by chj »

haberman wrote: post #15
andrewvc wrote: post #3

The X32 ABI is interesting. Who'd have thought this many years after 64 bit becoming mainstream, (and decades after it becoming mainstream on servers) something like this would be needed.

> Who'd have thought [...] Well, Donald Knuth for one. Here's a blog entry I wrote about Donald Knuth and how he asked for this a while back. I think it makes a lot of sense and I'm really glad to see this maturing! http://blog.reverberate.org/2011/09/making-knuth-wish-come-t...

Yeah, I remember this one:

http://www-cs-faculty.stanford.edu/~uno/news08.html

Saving 32bits means a lot to him.

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