Userspace checkpoint/restart hack: cryo

Nadia Derbey Nadia.Derbey at bull.net
Tue Apr 29 07:50:14 PDT 2008


Cedric Le Goater wrote:
> Dave Hansen wrote:
> 
>>A guy named Marc Vertes wrote this as a little demonstration of
>>checkpoint/restart.  I've been using it to experiment with
>>checkpoint/restart.  I thought it might be of some use as we move
>>subsystems to being helped by the kernel to checkpoint and restart.
>>
>>It's ptrace-based, and stuck on i386 for now.  It can probably be ported
>>elsewhere without too much trouble.    It doesn't support *anything
>>fancy like multuiple tasks :).  It has the advantage of being very
>>feature-bare, and I think it is pretty easy to hack on.  Whatever c/r
>>support we add to the kernel could easily be added on and tested.
>>
>>http://userweb.kernel.org/~daveh/cryo/cryo-001.tar.gz
>>
>>Usage:
>>	cr -p `pidof task` > checkpoint.cryo 
>>	cr -r < checkpoint.cryo
>>
>>If anyone else has something simpler or easier to hack on, I'm all ears.
> 
> 
> Indeed. It looks simple enough.
> 
> do you have some kernel requirement ? I run Fedora 8
> 
> Here's my first try on a program calculating decimal of PI : 
> 
> 	$ ./cr -p `pidof pi1` > pi1.cryo
> 	attaching to pid: 11082
> 	[11087 cr.c:243 getfdinfo()] n : 0
> 	WARNING (sci.c:242) unexpected signal for 11082: 11
> 	[11087 sci.c:228 ptrace_waitsyscall()] WTERMSIG(status) : 11
> 	ERROR (sci.c:383) ptrace_getregs(11082, 0xbfe4a3d0) errno=3: No such process
> 	./cr[0x8051f10]
> 	./cr[0x8049ce9]
> 	./cr[0x804b7d2]
> 	./cr[0x804f75b]
> 	***STOP***
> 
> other terminal :
> 
> 	$ pi1 20000
> 	pi1 - 20000 digits, 78.1 kbytes
> 	Segmentation fault (core dumped)
> 
> Thanks,
> 
> C.
> 

Looks like it has worked for me (msg1 creates 1000 msg queues, sleeps 
for a while and then removes the msg queues).

Output attached.

Regards,
Nadia



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