Re: [Valgrind-users] instruction trace

[David B. <dbr...@st...>]

> > I've used vtune to get instructions retired, but that is sort of on the
> > "opposite" end of the processor that I'm interested in.  [snip]
>  > For the paper, I'd like to compare instructions
> > issued vs. instructions retired for the two programs.  On the P4, those
> > two may not be the same for a number of weird P4 reasons (as I
> > understand talking to P4 experts). [snip]
> > I've tried valgrind with --single-step=yes, and see a couple of
> > different things that I think *may* be the instructions issued, like
> > "translate: new" in the output, but I'm not sure.  Is this instructions
> > issued?
> 
> All x86 implementations beginning with the Intel PentiumPro [ca.1995] have
> speculative, out-of-order execution, including along false conditional
> control paths (and even false _un_conditional control paths).  Speculation
> is influenced by code alignment, icache and dcache hits/misses, interrupts
> and task switches, CPU temperature, etc.  "Instructions issued" is almost
> meaningless for the hardware; certainly no software could ever compute it.


Thanks, that's good information but I'm not sure it completely answers
my question.  What I want is the number of assembly instructions issued,
then I can calculate with vtune the number of instructions retired.  It
would be interesting in it's own right just to compare the two...(esp.
since instructions retired is uops, not assembly instructions).  

I was hoping valgrind already would increment an instructions issued
variable before simulating the execution...this is all I really need for
right now.  Is this in the output of valgrind? 

After I get that number, i'll compare it to vtune's instructions retired
(running the program by itself w/o valgrind).

-david