Re: [Valgrind-developers] CPU Clock ticks

[Milind <km...@gm...>]

Thanks Josef for the reply. I am referring to CPU clock ticks and not the
wall clock. Couple of responses that I received also indicate that there is
no real CPU clock tick simulation. Let me see if I can cover my requirement
with the cachegrind output. I am sure I wont need full-system simulators
yet.

Thanks,
- Milind

On Tue, Jan 12, 2010 at 6:45 PM, Josef Weidendorfer <
Jos...@gm...> wrote:

> Hi,
>
> On Tuesday 12 January 2010, Milind wrote:
> > I have started exploring valgrind recently. I wanted to know if valgrind
> > core keeps track of the CPU clock ticks.
>
> Which ticks do you mean? Wall clock time makes not much sense, as this
> would
> include all housekeeping tasks Valgrind is doing, such as instrumentation
> of
> client code. So, there really is no "CPU clock tick" to keep track of.
> You have to maintain your own tick counter if you want something like this.
>
> And how you want this counter to advance is totally up to you and depends
> on
> the type of processor model you envision. E.g. you could include a cache
> model,
> a branch predictor, latency/troughput parameters for different instruction
> types and so on, and advance the clock tick counter accordingly.
> Just a note: it probably gets arbitrarily complex to approximate the tick
> counter
> of a real processor; and this only will work for the user-level side with
> one
> process.
>
> Perhaps it is better for you to look at cycle-accurate full-system
> simulators?
>
> Josef
>
> > I want to record memory access
> > pattern of my program. In that context, I wanted to record the CPU clock
> > tick value at the time of memory access. I want to feed output of
> valgrind
> > to DRAMsim which needs memory addr that is being accessed, access type
> > (read, write, etc) and the cpu clock time value when the access is being
> > done. Any pointers/links will help.
> >
> > Thanks,
> > - Milind
> >
>
>
>