I am not sure how many people actually follow the HPC forum on unix.com, but you may be interested in discussing the following (academic) problem:
Assume you want to run a *very* large number (say 100.000) of very lightweight synchronous operations. As an example, assume that you want to run 100.000 instances of
The trivial (aka braindead) approach would be
Takes about 15 years to finish ;-)
One could start 1000 threads, and run a sleep in each of them. That reduces the runtime to 100 hours - still 4 days, and the system is totally idle all the time.
So, using more threads? Won't work, as the max-threads-per-process limit will be hit at some point.
So, spawn 100 processes which spawn 1000 threads each?
The max-threads-per-process limit is, on Linux, close to the max-threads-per-system limit, so that won't work. On other Unixes that is different, but I don't think you get 100.000 threads on a normal single CPU system. Do you?
So, what would your approach be?
I am not looking for a sleep replacement: so saying that I should set alarm or something similar is of not much use. Sleep is obviously only an example here - replace it with an extremely lightweight job, like running a very time consuming synchronous remote operation.
I am looking forward to the ideas you guys can come up with! :-)
Cheers, Andre.
Last edited by Andre_Merzky; 02-11-2010 at 08:48 AM..
Reason: layout...
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