Re: [Qemu-devel] memory trace with qemu

[Eduardo Cruz]

Ok, I succeeded in adding the process tracker hack into qemu and
linux, and also in keeping track of the memory access (thanks Yufei
Chen for the tip).
I also simulated a cycle counter by counting the number of
instructions executed, which is equivalent to a cpu with cpi equals to
1.
But, as I am studying parallel programs behavior, I get very strange
results due to the fact that qemu executes thousands of instructions
of a cpu before moving to another cpu in smp systems.
I tried to limit this number, but it makes qemu very slow or even crash.
To achieve this, I added an helper that generates a timer event after
every X instructions executed.
I don't know If I am doing it in a wrong way.

Any suggestions?

2010/7/27 malc <address@hidden>
>
> On Tue, 27 Jul 2010, Jun Koi wrote:
>
> > On Mon, Jul 26, 2010 at 8:16 PM, malc <address@hidden> wrote:
> > > On Mon, 26 Jul 2010, Eliot Moss wrote:
> > >
> > >> On 7/26/2010 6:20 AM, Llu?s wrote:
> > >> > Eduardo Cruz writes:
> [..snip..]
>
> > >>
> > >> In the context of another simulator, we developed a different
> > >> technique, which would be quite general and might be of interest
> > >> for QEMU.  We communicate with the simulator via a "fake" *device*,
> > >> mapped into user-mode memory using an mmap call.  If someone
> > >> devised and coded such a device, then it could be used from any
> > >> guest.
> > >
> > > I'v done something similar a while ago:
> > > http://repo.or.cz/w/qemu/malc.git/shortlog/refs/heads/wctpci
> >
> > in this repo tree, which part is your new code?
> >
> > i looked at the git log, and tried to search your name, but none looks 
> > related.
>
> First five commits clearly have my nick in the second column, first
> three commits are directly related to the branch.
>
> --
> mailto:address@hidden


--
Eduardo Henrique Molina da Cruz
MSc student
Parallel and Distributed Processing Group
Federal University of Rio Grande do Sul (UFRGS)