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Why isn't AArch64 all over LWN? Surely the latest ARM news is singularly the most  important? There will be 4 or 5 Bosons, but there will be only one 64-bit ARM Architecture.
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Theodore Ts'o's profile photobirger monsen's profile photoThorsten Leemhuis's profile photoArjan van de Ven's profile photo
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but - where can i get one? 'raspberry master'?
 
Editors have a right to take a weekend off, too ;-) (says a editor that just used his free time on a Saturday evening  to catch up with #lkml...)
 
+Jon Masters there are like 9 different ARM 32 bit architectures... I sort of doubt the 64 bit side will stay single for long.
 
CPU power consumption is only a part of the total power consumption story of a server.  IMHO, it remains to be seen if the ARM-64 manufacturers can deliver on a server which (a) has a balanced amount of HDD's, memory bandwidth, network, and CPU capabilities so you can actually use of the server's resources efficiently, and (b) has a total overall efficient power utilization curves once you take into account the power usage levels of the networking card, the memory, the HDD's, etc.
 
+Theodore Ts'o Right. The real story is Hyperscale, not ARM or Intel or whatever CPU component.
 
+Theodore Ts'o that's the big reason i would love to see some relevant benchmarking of 64bit arm vs ivy bridge for some kind of LAMP-server benchmark. not only for the transactions/watt, but also to see where the bottlenecks would be in the first iterations on ARM.
 
On an Intel server, when it's idle, the vast bulk of the power is in the memory, the IO's (SATA, network, PCI etc). The CPU power itself is very small (due to power gating of the cores and the caches).
The "chipset" is the vast bulk of the power..

When a CPU is in use, the power consumption is defined by physics quite a bit. Yes architecture of the design/instructionset/etc matter, but both Intel and ARM are well designed, and the differences there will be < 20% between the two (you can argue in which direction). By and large, power goes squared to peak performance, and you can pick a design point on such a curve and design for that. Traditionally ARM guys picked a low point, and Intel a high point. But nowadays you can get either point from either...
 
and exactly that is part of the hyperscale architecture(s), +Arjan van de Ven . bring down power consumption all over the chipset.
 
s/chipset/chip/ && point made
 
+Thorsten Leemhuis Clearly I'm just trying to be witty. Even I occasionally enjoy time away from the computer ;) Though I did spend a lot of evenings last year reading AArch64 docs.
 
+Jonathan Corbet hey, that patch stream is awesome. For some bizarre reason I didn't realize you exposed that, that's cool.
 
I'm just super excited this stuff is now getting out there and we can start talking more broadly about it - AArch64 has been one of those things keeping me warm at night for a while. Very keen to see this supported in Fedora as soon as possible.
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