Hi Gene,
Thank you for this information it is very helpful.
I have noticed that "the header section" , "the header for each contiguous
memory area" and 'the data for each contiguous memory area' are all multiples
of 4K (which is the page size).
Does this means that other headers (written by plugins) to "represent
additional state in their memory, for the kernel state, state of the network,
data in flight in sockets, etc." are also muliple of 4k ?
This other headers are also included in the ckpt_*.dmtcp ?
How big is this headers (how many pages) ?
Looking forward for your reply.
Best regards,
Ramy Gad
Johannes Gutenberg - Universität Mainz
Zentrums für Datenverarbeitung (ZDV)
Anselm-Franz-von-Bentzel-Weg 12
55128 Mainz
Germany
E-Mail: g...@uni-mainz.de
Office Phone: +49-6131-39-26437
________________________________________
From: Gene Cooperman <g...@ccs.neu.edu>
Sent: Friday, March 27, 2015 8:20 PM
To: Gad, Ramy
Cc: Gene Cooperman; dmtcp-forum@lists.sourceforge.net
Subject: Re: [Dmtcp-forum] How similar is DMTCP checkpoint file to a process
core memory dump ?
Hi Ramy,
Unfortunately, the best document for that is the code for
util/readdmtcp.sh. This will lead you to:
src/mtcp/mtcp_restart.cpp with the flag --simulate, which will
lead you to the function mtcp_simulateread().
I would run this under GDB. It's less painful than searching for
the headers in the .h file. So:
cp ckpt_*.dmtcp > tmp.dmtcp.gz
gunzip tmp.dmtcp.gz
gdb --args bin/mtcp_restart --simulate tmp.dmtcp
(gdb) b mtcp_simulateread
(gdb) run
You'll then want to do things like:
(gdb) b main
(gdb) run
(gdb) b 258
(gdb) c
(gdb) p mtcpHdr # second header (how to read the memory areas)
(gdb) b 284
(gdb) p rinfo # first header (organization of ckpt image)
# Then continue to loop, and read the detailed header of each memory area
(gdb) ptype area
(gdb) p area
Best,
- Gene
On Fri, Mar 27, 2015 at 04:16:20PM +0000, Gad, Ramy wrote:
> Hi,
>
> Is there any detail documentation that can explain how to decode the
> ckpt_*.dmtcp file ?
>
> i.e. decode
>
> 1) the header section
> 2) the header for each contiguous memory area (addr range, permissions, etc.)
> 3) the data for each contiguous memory area
>
> I want to know exactly where are the heap, the stack and dynamic libraries,
> etc. in the ckpt_*.dmtcp file
>
> Having a documentation is a easier than reverse engineering the code :-)
>
> Thank you in advance for your reply.
>
> Best regards,
>
> Ramy Gad
> Johannes Gutenberg - Universität Mainz
> Zentrums für Datenverarbeitung (ZDV)
>
> Anselm-Franz-von-Bentzel-Weg 12
> 55128 Mainz
> Germany
> E-Mail: g...@uni-mainz.de
> Office Phone: +49-6131-39-26437
>
>
> ________________________________________
> From: Gene Cooperman <g...@ccs.neu.edu>
> Sent: Wednesday, March 18, 2015 6:54 PM
> To: Gad, Ramy
> Cc: dmtcp-forum@lists.sourceforge.net
> Subject: Re: [Dmtcp-forum] How similar is DMTCP checkpoint file to a process
> core memory dump ?
>
> Hi Ramy,
> DMTCP is very similar to a process core memory dumps, but it
> uses its own internal format, with certain enhancements. It includes:
> 1) a header section
> 2) a header for each contiguous memory area (addr range, permissions, etc.)
> 3) the data for each contiguous memory area
>
> A memory area with zero pages is saved specially to save space.
>
> If you want to look at a DMTCP ckpt image, do:
> gzip -dc ckpt_*.dmtcp > tmp.dmtcp
> <DMTCP_DIR>/util/readdmtcp.sh tmp.dmtcp
>
> You'll see that DMTCP also saves the memory of all resident libraries.
> In particular, the DMTCP libraries (plugins) will save additional state
> in their memory, for the kernel state, state of the network, data in
> flight in sockets, etc.
>
> Best,
> - Gene
>
>
> On Wed, Mar 18, 2015 at 03:45:16PM +0000, Gad, Ramy wrote:
> > Hi all,
> >
> >
> > How similar is DMTCP checkpoint file to a process core memory dump ?
> >
> >
> > What are the common info and what are the differences ?
> >
> >
> > Best regards,
> >
> > Ramy Gad
> > Johannes Gutenberg - Universität Mainz
> > Zentrums für Datenverarbeitung (ZDV)
> >
> > Anselm-Franz-von-Bentzel-Weg 12
> > 55128 Mainz
> > Germany
> > E-Mail: g...@uni-mainz.de<mailto:g...@uni-mainz.de>
> > Office Phone: +49-6131-39-26437
> >
>
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