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Comment: Re:SVLTE/SVDO? (Score 1) 47

by rmav (#46693949) Attached to: Qualcomm Announces Next-Gen Snapdragon 808 and 810 SoCs
Well, ok, now I see the connection, but, again, these are two independent things. SVLTE can be implemented today already. It was done already with the MSM8960 and MDM9x15 from 2012, using only one baseband (previous solutions used two) but required additional antennas (IIRC three, and two RF chips).

Comment: Re:"There's zero benefit a consumer gets from that (Score 4, Informative) 47

by rmav (#46691601) Attached to: Qualcomm Announces Next-Gen Snapdragon 808 and 810 SoCs

Now that one person is doing it, everyone is going to have to do it. It's going to be difficult selling a 32-bit processor when the guy across the street is selling a 64-bit one.

There's a lot more reason to go 64 bit than that. The biggest is that it's not going to be long before smartphones and tablets have > 3 GiB RAM. Yeah, there are all sorts of workarounds you can use to access larger amounts of RAM with 32-bit pointers, but it's much nicer to have a flat address space, including plenty of address space for memory-mapped devices. Granted that we're probably a couple of years away from needing 64 bits, but it's coming, fast.

32-bit ARM already addresses more than 32 bits: recent 32 bit ARM architectures have a 48 bit address space, and several chips support 36 or 40 bits. The problem of individual applications addressing at most 32 bits is minor, at this stage, but sooner or later we will have big graphics editing applications on Tablets, and larger address spaces help.

The main advantage that Aarch64 has at this very moment is that it offers a more streamlined instruction set (that makes instructions easier to reorder) and more registers. Even just compiling 32 bit code in the new model you can get impressive performance gains.

Roberto

Comment: Re:SVLTE/SVDO? (Score 4, Informative) 47

by rmav (#46691575) Attached to: Qualcomm Announces Next-Gen Snapdragon 808 and 810 SoCs

So does this finally mean we'll get Simultaneous voice and LTE/SVDO back?

64-bit ARM and support for simultaneous voice and LTE/SVDO are completely different things.

The 64-bit ARM cores are application processors (AP). They do not control the modem (that can be part of the SoC together with the AP or an external component): Qualcomm modems have nifty internally developed (and publicly documented) a VLIW CPU called "Hexagon" that offers DSP-like instructions to control the modem. Some modems have two, and another Hexagon is used to process audio and cal also run user provided applications. You can find some information here http://en.wikipedia.org/wiki/Q... and a lot more is linked.

And even this has nothing to do with dual radios. They are independent things.

Roberto

Comment: Re:What can be wrong with Clang! (Score 1) 711

by rmav (#40014235) Attached to: FreeBSD 10 To Use Clang Compiler, Deprecate GCC

Run time optimizations can be (are?) a very bad idea in a kernel, where very often the exact predictability of execution paths makes the difference between a working kernel and a misbehaving one.

Well, with Clang/LLVM you can compile the kernel straight to the target architecture with run time optimization turned off, as well as building what else you want, for instance your applications, with run time optimization turned on. Easy as customizing your Makefiles.

Roberto

Comment: Re:What's wrong with GCC? (Score 1) 711

by rmav (#40003915) Attached to: FreeBSD 10 To Use Clang Compiler, Deprecate GCC

Here are some facts. GCC 4.6.3 Loses to Clang 3.0 50% of the time. GCC 4.6.3 Loses to Clang 3.0 ~18% of the time. Most of the benchmarks use OpenMP which clang doesn't support. GCC 4.6.1 Loses to a prerelease Clang 3.0 ~50% of the time.

Where are you getting this 90% from? Cause it's not from reality.

I also get quite variable results. I have some code that runs significantly faster with gcc 4.6.x or 4.7.x. Other code is faster with clang 3.0. It really depends. In my experience gcc is more faster than not, but the gat is closing quickly. Roberto

Comment: Re:Quite right (Score 1) 228

by rmav (#34600040) Attached to: The Clock Is Ticking On Encryption

Of course, there are other encryption schemes that seem to work just fine (e.g. Elliptic curve cryptography) with quantum computing, and there's not much evidence that algorithms other than RSA are broken.

Actually, all discrete-logarithm based schemes can be broken in polynomial time by quantum computing, hence also elliptic curve cryptography.The details have to be re-worked out for each such scheme, but that's true also of any classical attack. See for instance http://www.mathcs.richmond.edu/~jad/summerwork/ellipticcurvequantum.pdf

Roberto

Comment: Re:Silvio Berlusconi (Score 1) 150

by rmav (#32912260) Attached to: Italian Draft Wiretapping Law Under Fire

Skimming, kickbacks, outright bribery. Sadly it seems the only way people get anything done in this city is if they can take a slice off the top. The honest guys and small time thieves have little incentive to really push things. The deeply corrupt get an awful lot done. One percent off the top gets to be a larger amount the more they accomplish.

Still, I do not like that...

Comment: Re:Silvio Berlusconi (Score 1) 150

by rmav (#32902470) Attached to: Italian Draft Wiretapping Law Under Fire

It is still better an honest incompetent than an outright criminal in charge. I'm not so sure about that. I'd rather have a competent judge who fixes traffic tickets for his friends than an incompetent one. Of course, worse is one who is both crooked and incompetent.

Well, there are smaller misbehaviours and bigger things. To fix traffic tickets for friends is of course a crime, but it would be difficult to consider it a major crime (even though it gives a very bad example, and can ruin the trust between citizen and institutions). But a prime minister with ties to the mafia, that is totally unacceptable.

Roberto

Never try to teach a pig to sing. It wastes your time and annoys the pig. -- Lazarus Long, "Time Enough for Love"

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