On Apr 21, 2006, at 6:51 AM, Rustam Muginov wrote:
Hello all.
Recently I've started to port and optimize our software for intel-
based macs.
I am using macmini (core duo 1.66 GHz) with OS X 10.4.6, XCode
2.2.1 and CHUD Tools 4.3.2
I've got several questions about Shark on intelmacs
1) The "Cycles" column sometime shows "N/A" for some instruction.
Why where are no information for instruction latency/throughoutput?
I'll risk an answer here, some of these are just not documented by
Intel (have a look at their Optimization Guides). If Apple engineers
were going by the published docs, and didn't have any special info
from Intel, you'll find some instructions' latency and throughput
won't be listed indeed. I believe all of MMX/SSE/SSE2 instructions
were documents, and many of the `most used' integer instructions --
not sure where FP stands though.
2) So far most of the warnings are only "LCP" warning/advice for
the code, recommending me to change loop counters from 16-bit to 32-
bit integers. I can not see any stalls, i was getting plenty of
stall warning for PowerPC code. Does this mean such info is not
available while profiling intel code?
3) The Advanced options only show two possible CPUs, Pentium 4 and
Pentium M. Which intel-based macs model has Pentium 4 and which has
Pentium M CPUs?
Pentium 4 on the dev kits, Pentium M (actually now called Core Solo/
Duo) on the production boxes.
And another question about optimization.
I would like to compare how worse code would behave if compiler
wont use the SSE/SSE2 instruction for scalar floating point, and
try to compile code to use only x387 math. Which additional
compiler flags I should pass to gcc to prohibit usage of SSE/SSE2?
I believe -mno-sse and -mno-sse2.
Décio
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