K.S. Bhaskar on 18 Apr 2016 11:51:29 -0700

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Re: [PLUG] >32K concurrent processes

Rich --

Yes, in a high volume production environment there are many context switches - at least tens of thousands per second, perhaps hundreds of thousands per second (I don't have the numbers from a benchmark at my finger tips, so I can't comment on actual numbers).

-- Bhaskar

On Mon, Apr 18, 2016 at 12:43 PM, Rich Freeman <r-plug@thefreemanclan.net> wrote:
On Mon, Apr 18, 2016 at 11:49 AM, K.S. Bhaskar <bhaskar@bhaskars.com> wrote:
> Thanks for the suggestions, Gavin, but batching the load won't work in this
> case. We're trying to run a workload that simulates a large number of
> concurrent users (as you might find at a large financial or healthcare
> institution) all of whom expect the system to respond immediately when they
> ask it to do something. I intend to play with the scheduler.

My understanding is that linux uses an O(1) scheduler so it shouldn't
bog down in actual task switching.  Now, of course that doesn't change
the fact that your CPUs are split 32k ways.  You probably could tune
how much time each process gets in a slice, or how they're prioritized
when there is contention.

I'm not actually sure that 2 processes switching back and forth 10k
times in a second is any better than 10k processes switching back and
forth once each in a second.  Obviously with more processes each gets
less time, but the overhead of task switching itself may not change by

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