Messages in this thread | | | From | Hubertus Franke <> | Subject | Re: Analysis for Linux-2.5 fix/improve get_pid(), comparing various approaches | Date | Fri, 9 Aug 2002 14:18:07 -0400 |
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On Friday 09 August 2002 12:05 pm, Linus Torvalds wrote: > On Fri, 9 Aug 2002, Hubertus Franke wrote: > > I dragged the various algorithms into a userlevel test program to figure > > out where the cut off points are with PID_MAX=32768. In this testprogram > > I maintain A tasks, and for 10 rounds (delete D random tasks and > > reallocate D tasks again) resulting in T=10*D total measured allocations. > > Mind re-doing that with PID_MAX=999999 or similar? The whole point of the > current simple algorithm is that the common case (nay, done right, the > _only_ case) is where the number of threads << PID_MAX. >
Don't have time right now... Simply look at the numbers for the ratio you are expected. I would be very surprise if the relative curves would change when moving to 132K tasks and also populate the pid space only by let's say 25%.
Otherwise, Paul can you run this....
> That certainly used to be true with PID_MAX=32768 (not many people may > realize it, but in 1991 the maximum number of tasks in the system was > limited to 63, simply because of how the VM carved out the 4GB address > space). > > Things have changed, but considering that some people think that 32k > threads are a limitation already, and that the current code should work > fine (and be pretty much optimal) with a larger PID_MAX, I really think > it's unfair to not even benchmark that case.. > > Linus
-- -- Hubertus Franke (frankeh@watson.ibm.com) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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