A question on PPC32

A question on PPC32

[chen HJ]

Hi all,

A simple question, can systemTap support PPC32 now? I have tried to
compile systemTap on MPC5121, but it needs a header file for PPC64.

Best Regards,
H.J

Re: A question on PPC32

[Ananth N Mavinakayanahalli]

On Mon, Jun 29, 2009 at 04:24:03PM +0800, chen HJ wrote:
> Hi all,
> 
> A simple question, can systemTap support PPC32 now? I have tried to
> compile systemTap on MPC5121, but it needs a header file for PPC64.

The kernel side support (kprobes, tracepoints, et al) are already
available. Its quite possible that the SystemTap runtime needs a few
tweaks to get it working for ppc32

Look at __powerpc64__/__arm__ in runtime code and see if a new stub
needs to be written at those places for __powerpc__

Ananth

Re: A question on PPC32

[Ananth N Mavinakayanahalli]

On Mon, Jun 29, 2009 at 03:30:22PM +0530, ashok.shanmugam@wipro.com wrote:
> >On Mon, Jun 29, 2009 at 04:24:03PM +0800, chen HJ wrote:
> >> Hi all,
> >>
> >> A simple question, can systemTap support PPC32 now? I have tried to
> >> compile systemTap on MPC5121, but it needs a header file for PPC64.
> 
> >The kernel side support (kprobes, tracepoints, et al) are already
> >available. Its quite possible that the SystemTap runtime needs a few
> >tweaks to get it working for ppc32
> 
> >Look at __powerpc64__/__arm__ in runtime code and see if a new stub
> >needs to be written at those places for __powerpc__
> 
> >Ananth
> 
> 
> 
> Hi Ananth,
> 
> Can you tell me from which kernel version the PPC32 is supported for kprobes ?

Kumar Gala added the patch (git commit 8209003) in Feb 2007. AFAICS, kprobes
for ppc32 has been available since 2.6.21.

Ananth

Re: A question on PPC32

[chen HJ]

Hi all,

Thanks for your response, can you provide any more detailed steps
about how to make systemTap work on PPC32?

Best Regards,
H.J


On Mon, Jun 29, 2009 at 6:18 PM, Ananth N
Mavinakayanahalli<ananth@in.ibm.com> wrote:
> On Mon, Jun 29, 2009 at 03:30:22PM +0530, ashok.shanmugam@wipro.com wrote:
>> >On Mon, Jun 29, 2009 at 04:24:03PM +0800, chen HJ wrote:
>> >> Hi all,
>> >>
>> >> A simple question, can systemTap support PPC32 now? I have tried to
>> >> compile systemTap on MPC5121, but it needs a header file for PPC64.
>>
>> >The kernel side support (kprobes, tracepoints, et al) are already
>> >available. Its quite possible that the SystemTap runtime needs a few
>> >tweaks to get it working for ppc32
>>
>> >Look at __powerpc64__/__arm__ in runtime code and see if a new stub
>> >needs to be written at those places for __powerpc__
>>
>> >Ananth
>>
>>
>>
>> Hi Ananth,
>>
>> Can you tell me from which kernel version the PPC32 is supported for kprobes ?
>
> Kumar Gala added the patch (git commit 8209003) in Feb 2007. AFAICS, kprobes
> for ppc32 has been available since 2.6.21.
>
> Ananth
>

Re: A question on PPC32

[Ananth N Mavinakayanahalli]

On Tue, Jun 30, 2009 at 08:11:29AM +0800, chen HJ wrote:
> Hi all,
> 
> Thanks for your response, can you provide any more detailed steps
> about how to make systemTap work on PPC32?

On first glance, additions/modifications would be required to
runtime/regs.c runtime/regs.h runtime/string.h runtime/copy.c

Look for all instances of arch specific code in the above files and
you'll need to add or modify existing stubs for it to work on powerpc.

Further, you'll need to build and run SystemTap to determine if any
other changes would be needed for ppc32 enablement.

Ananth

Re: A question on PPC32

[Jim Keniston]

On Tue, 2009-06-30 at 14:41 +0530, Ananth N Mavinakayanahalli wrote:
> On Tue, Jun 30, 2009 at 08:11:29AM +0800, chen HJ wrote:
> > Hi all,
> > 
> > Thanks for your response, can you provide any more detailed steps
> > about how to make systemTap work on PPC32?
> 
> On first glance, additions/modifications would be required to
> runtime/regs.c runtime/regs.h runtime/string.h runtime/copy.c
> 
> Look for all instances of arch specific code in the above files and
> you'll need to add or modify existing stubs for it to work on powerpc.
> 
> Further, you'll need to build and run SystemTap to determine if any
> other changes would be needed for ppc32 enablement.
> 
> Ananth

You'll probably need to add a "ppc" subdirectory* to the tapset
directory, with registers.stp and syscalls.stp.  (*I don't have a ppc32
box handy.  I think that the subdirectory name is supposed to match
whatever "uname -m" reports.)

If you want to probe functions in user-space programs -- e.g.,
    probe process("myprog").function("myfunc") { ... }
you'll need to port uprobes.  This probably means cloning and/or editing
runtime/uprobes/uprobes_ppc64.{c,h}, and making the obvious changes to
uprobes_arch.{c,h} in runtime/uprobes and runtime/uprobes2.  In case
it's not clear what the functions and macros in uprobes_ppc64.{c,h} are
supposed to do, I can mail you the uprobes porting guide.

Jim Keniston

RE: A question on PPC32

[Chen Hongjun-R66092]

Hi Ananth,

Thanks a lot! 

Best Regards,
H.J


> -----Original Message-----
> From: Ananth N Mavinakayanahalli [mailto:ananth@in.ibm.com] 
> Sent: Tuesday, June 30, 2009 5:12 PM
> To: chen HJ
> Cc: ashok.shanmugam@wipro.com; systemtap@sourceware.org
> Subject: Re: A question on PPC32
> 
> On Tue, Jun 30, 2009 at 08:11:29AM +0800, chen HJ wrote:
> > Hi all,
> > 
> > Thanks for your response, can you provide any more detailed steps 
> > about how to make systemTap work on PPC32?
> 
> On first glance, additions/modifications would be required to 
> runtime/regs.c runtime/regs.h runtime/string.h runtime/copy.c
> 
> Look for all instances of arch specific code in the above 
> files and you'll need to add or modify existing stubs for it 
> to work on powerpc.
> 
> Further, you'll need to build and run SystemTap to determine 
> if any other changes would be needed for ppc32 enablement.
> 
> Ananth
> 

question about cache miss

[tgh]

Hi
	I want to know whether we can get cache miss information from
systemtap, or how to get it, could you give me some examples 

Thank you
 

Re: question about cache miss

[William Cohen]

tgh wrote:
> Hi
> 	Does systemtap support cache miss instrumentation ? how to get it
> 
> thanks
> 

You mean the processor's L1/L2/L3 cache? SystemTap doesn't have access to the
performance monitoring hardware on the processors. You might look at the
Performance Counters for Linux (PCL) which has been pulled into the 2.6.31 kernel:

http://lwn.net/Articles/324775/
http://www.h-online.com/open/Kernel-Log-Main-development-phase-of-Linux-2-6-31-completed--/news/113614

The current PCL implementation doesn't have a interface available for the kernel
calls. This makes it a bit difficult for SystemTap to use it.

If you are talking about software caches in the kernel, you might be able to
find the appropriate functions to probe to allow systemtap to observe those
events. Something similar to the the vm.pagefault probe.

-Will

question about cache miss

[tgh]

Hi
	Does systemtap support cache miss instrumentation ? how to get it

thanks