On Fri, Jan 16, 2015 at 9:38 AM, David Crayford <[email protected]> wrote:
> On 16/01/2015 11:16 PM, John McKown wrote: > >> On Fri, Jan 16, 2015 at 8:24 AM, Bob Shannon <[email protected] >> > >> wrote: >> >> So, as an extremely silly example. SMT will not "help" in the following >>>> >>> program: I.e. in a "hard loop" which uses data & instructions >>> >>> There are exceptions to every rule. If that’s the type of workload you >>> run, turn SMT off. >>> >>> Bob Shannon >>> Rocket Software >>> >>> Basically, I'm trying to conceptualize how z SMT compares to Intel's. >> > > Better to compare it to the POWER arch http://www-03.ibm.com/systems/ > resources/pwrsysperf_SMT4OnP7.pdf. > It may be CISC not RISC but those lines are getting more blured with every > new churn of z. I would imagine that the > SIMD vector units also originate from POWER. It may seem far fetched but > I can see a time in the not too distant future > when the two architectures are converged. > I said something similar to that on the IBMVM forum. Alan Altmark (alter ego: "Chuckie") of IBM, but not speaking for IBM, said that _he_ did not think this was likely. I was envisioning a single CEC running the z, i, and p software in different hardware partitions. But given the zBX and some "fundamental internal architecture differences" between the z and p chips, I guess this is unlikely. Unless IBM makes a z/PDT type "dongle" and an instruction emulator for the Power platform. Again, unlikely. > > >> > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > -- While a transcendent vocabulary is laudable, one must be eternally careful so that the calculated objective of communication does not become ensconced in obscurity. In other words, eschew obfuscation. 111,111,111 x 111,111,111 = 12,345,678,987,654,321 Maranatha! <>< John McKown ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
