On 1/24/2014 4:20 PM, John McKown wrote:
On Fri, Jan 24, 2014 at 4:58 PM, Ed Jaffe <edja...@phoenixsoftware.com>wrote:
Perhaps JG's assertion is actually about "grande" instructions vs "normal"
instructions. Our benchmarks show grande instructions are ever-so-slightly
(<2%) slower than their non-grande counterparts. Example: L vs LG.
Of course, the instruction path for the six-byte grande "LG" benchmark
code is 50% larger (in terms of space occupied, not instructions issued)
than its four-byte non-grande "L" counterpart, meaning more i-cache is
required to run it. So, perhaps that is to what this <2% difference is
attributable.
Either way, it's something we consistently observe...
In cases like this, it might be helpful to know the _exact_ machine you're
running on, or if this is one a number of different machine types. z9BC,
z9EC, z10BC, z10EC, and so on.
Latest benchmarks run on full-speed zIIP engine of a zBC12.
--
Edward E Jaffe
Phoenix Software International, Inc
831 Parkview Drive North
El Segundo, CA 90245
http://www.phoenixsoftware.com/
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