[External] : Re: jstack, profilers and other tools

[Alex Otenko]

I agree about capacity to do work. What I don't agree with is that you can
change concurrency to increase throughput in Little's law - not more than
you can change acceleration to increase force.

And I don't agree that the common bottleneck is the lack of threads - 10k
threads on 100 CPUs is not much; 10k longlived threads on 1 CPU is 99.99%
waiting. Shortlived threads, or thread per request, isn't really about
concurrency in Little's law.


Alex

On Fri, 15 Jul 2022, 15:05 Pedro Lamarão, <pedro.lamarao at prodist.com.br>
wrote:

> Em sex., 15 de jul. de 2022 às 05:39, Alex Otenko <
> oleksandr.otenko at gmail.com> escreveu:
>
>
>> Adding threads allows to do more work. But you can't do more work at will
>> - the amount of work going through the system is a quantity independent of
>> your design.
>>
>
> I think that, more precisely, the maximum amount of work that can go
> through a concrete system is a quantity independent of programmer design.
> Nobody is arguing that increasing the quantity of threads will increase
> work throughput in a machine with devices already at full capacity.
> What is being argued is that, since "task" is one of the machine's
> "devices" consumed to do work,
> increasing the capacity for "tasks" increases the maximum amount of work
> that can go through etc.
> If there are free processors, free memory, free network bandwidth, free
> storage bandwidth etc. etc. then doing more work concurrently will increase
> work throughput.
>
> --
> Pedro Lamarão
>
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