Oren> For now, yes. But we definitely want this capability in the long
Oren> run; otherwise we won't be able to checkpoint a kernel compile
Oren> ('make' uses vfork), or anything with 'gdb' running inside, or
Oren> 'strace', and other goodies.

The strace/gdb example is *really* hard; but for vfork, you just wait
until it's over. The interval between vfork and exec/exit should be
short enough not to affect the overall time for a checkpoint (and
checkpoint can be fairly slow anyway --- on the HPC machines we used
to do it on, writing half a terabyte of checkpoint image to disc could take
many minutes.  In hindsight, we should have multithreaded it).

we've tried that and it doesn't change a thing if you have only one disk :)
it might even give worse results as you are increasing context switches.

Waiting for a vforked process to exec is less than a millisecond.

yes that shouldn't be too hard to handle.

Cheers,

C.

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