4 ms·

Explain?

Symmetry 16y ago
With Sandybridge Intel created a new set of instructions to replace/supplement SSE. There are some nice things about them that ought to mean that they should have higher performance. However, no existing software uses them so the AVX stuff isn't being used right now. In N months when software has code execution paths using AVX we might see these guys pull ahead of Nehalem processors. AMD will have its own processors using AVX coming out soon too.
- Symmetry 16y ago
  On thing I didn't realize immediately. Since the larger registers are program state that has to be stored and restored between thread switches you need operating system support before you can enable AVX. Apparently this is coming to Windows in service pack 1 of Windows 7.
Tuna-Fish 16y ago
The AVX extension adds a set of new instructions that can operate on 256 bits of data at once (in the form of 4 64-bit floats, 8 32-bit floats, or various other data types), and the new registers to fit them in. These new instructions promise to significantly increase throughput for a limited set of operations -- but to do that, the software has to be compiled to use them, and often entirely rewritten to use the wider vectors. Few will bother to do that until the new instructions have significant market penetration -- which will take years. I am not quite as optimistic as Symmetry is about the usefulness of these latest extensions to x86 -- while many fringe tasks will benefit a lot, most of what you do on a computer just isn't limited by the width of the vectors or the amount of SIMD operations you can do per clock. IMHO, the insanely fast caches are a much more significant improvement.
- adrianN 16y ago
  Those extensions may not be very interesting for the consumer market, but scientific applications will probably see more benefits.
- xpaulbettsx 16y ago
  They also allow the CPU register context to be saved/loaded with a single instruction as well, User-Mode Scheduler in Win7 SP1 uses it (the normal scheduler too afaik).
  - Tuna-Fish 16y ago
    That's a single microcoded instruction -- those are not typically any faster than a bunch of normal instructions.

Explain?

With Sandybridge Intel created a new set of instructions to replace/supplement SSE. There are some nice things about them that ought to mean that they should have higher performance. However, no existing software uses them so the AVX stuff isn't being used right now. In N months when software has code execution paths using AVX we might see these guys pull ahead of Nehalem processors. AMD will have its own processors using AVX coming out soon too.

Symmetry 16y ago
On thing I didn't realize immediately. Since the larger registers are program state that has to be stored and restored between thread switches you need operating system support before you can enable AVX. Apparently this is coming to Windows in service pack 1 of Windows 7.

Tuna-Fish 16y ago

The AVX extension adds a set of new instructions that can operate on 256 bits of data at once (in the form of 4 64-bit floats, 8 32-bit floats, or various other data types), and the new registers to fit them in. These new instructions promise to significantly increase throughput for a limited set of operations -- but to do that, the software has to be compiled to use them, and often entirely rewritten to use the wider vectors. Few will bother to do that until the new instructions have significant market penetration -- which will take years. I am not quite as optimistic as Symmetry is about the usefulness of these latest extensions to x86 -- while many fringe tasks will benefit a lot, most of what you do on a computer just isn't limited by the width of the vectors or the amount of SIMD operations you can do per clock. IMHO, the insanely fast caches are a much more significant improvement.

adrianN 16y ago
Those extensions may not be very interesting for the consumer market, but scientific applications will probably see more benefits.
xpaulbettsx 16y ago
They also allow the CPU register context to be saved/loaded with a single instruction as well, User-Mode Scheduler in Win7 SP1 uses it (the normal scheduler too afaik).
- Tuna-Fish 16y ago
  That's a single microcoded instruction -- those are not typically any faster than a bunch of normal instructions.