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ARM Readies Cores For 64-Bit Computing
snydeq writes "ARM Holdings will unveil new plans for processing cores that support 64-bit computing within the next few weeks, and has already shown samples at private viewings, InfoWorld reports. ARM's move to put out a 64-bit processing core will give its partners more options to design products for more markets, including servers, the source said. The next ARM Cortex processor to be unveiled will support 64-bit computing. An announcement of the processor could come as early as next week, and may provide further evidence of a collision course with Intel."
I know folks think it's 'overkill' to have 64-bit CPUs in portable devices, but consider that the -entirety- of storage and RAM can be mmapped in the 64-bit address space... That opens up a lot of options for stuff like putting entire applications to sleep and instantly getting them back, distributing one-time-use applications that are already running, sharing a running app with another person and syncing the whole instance (not just a data file) over the Internet, and other cool futuristic stuff.
I'm wondering when the first server/desktop OS is going to come out that realizes this and starts to merge the 'RAM' and 'Storage' into one 64-bit long field of 'fast' and 'slow' storage. Say goodbye to Swap, and antiquated concepts like 'booting up' and 'partitions'.
"Sometimes, I think Trent just needs a cup of hot chocolate and a blankie." -Tori Amos on Nine Inch Nails
Would be the most exciting revolution to watch. Since it has a totally different design it changes the parameters of how hardware end products can be built.
As ARM cores are so simple and ARM Holding does not have their own fabs, anyone could come up with their own optimized ARM-compatible CPUs. It's one of those moments when the right economics and the right technology could fuse together and change stuff.
Can you please explain the advantage of ARM over X86 in the server room because this one has me scratching my head. While I'm all for different arches (I have a PPC G3 Mac just so I could play with non x86) I thought the whole point of ARM was it was super low power for mobile devices? while I'm sure cutting down power usage in the server room would not be a BAD thing, considering how much software, both for Windows AND Linux, that isn't for ARM based CPUs I just don't get what the advantage of this would be over say a Bobcat, Nano, or Atom based solution.
Now in mobile I get it, as you can make a cheap iPad knockoff that can get 8+ hours of battery life, but in servers? Maybe there is a use case I don't know of, but when I was setting up servers while power was a consideration it certainly wasn't looked at as a priority over the performance in server roles. How well does ARM handle large amounts of users? How well does it scale with increased demands? While I wish them all the best I just haven't seen a screaming need for these, not when you already have Atom and Nano and are about to have Bobcat and Bulldozer (which from the looks of it will be nice as it has a well built GPU in the Bobcat and Bulldozer so AMD stream coding could be used) all in that same market. What am I missing here?
ACs don't waste your time replying, your posts are never seen by me.
It should in theory scale better than x86-64 anyhow, and the performance per watt is quite superior, so yes, it has a major place in the server room.
This isn't like the 16->32 bit transition where it quickly became apparent that the benefits were large enough and the costs both small enough and rapidly decreasing that all but the smallest microcontrollers could benefit from both the switch and the economies of scale. 64-bit pointers help only in select situations, they come at a large cost, and as fabs start reaching the atomic scale we're much less confident that Moore's Law will decrease those costs to the level of irrelevance anytime soon.
Most uses don't need >4 gigabytes of RAM, and it takes extra memory to compensate for huge pointers. Cache pressure increases, causing a performance drop. Sure, often x86-64 code beats 32-bit x86 code, but that's mostly because x86-64 adds registers on a very register-constrained architecture and partly because of wider integer and FP units. 64-bit addressing is usually a drag, and it's the addressing that makes a CPU "64-bit". ARM doesn't have a similar register constraint problem, and the cost of 64-bit pointers would be especially obvious in the mobile space, where cache is more constrained- one of the most important things ARM has done to increase performance in recent years was Thumb mode i.e. 16-bit instructions, decreasing cache pressure.
Most of those who do need more than 4GB don't need more than 4G of virtual address space for a single process, in which case having the OS use 64-bit addressing while apps use 32-bit pointers is a performance boon. The ideal for x86 (which nobody seems to have tried) would be to have x86-64 instructions and registers available to programs but have the programs use 32-bit pointers, as noted by no less than Don Knuth:
It's funny to continually hear people clamoring for native 64-bit versions of their applications when that often will just slow things down. One notable instance: Sun/Oracle have told people all along not to use a 64-bit JVM unless they really need a single JVM instance to use more than 4GB of memory, and the pointer compression scheme they use for the 64-bit JVM is vital to keeping a reasonable level of performance with today's systems.