Re: Queues just aren't scalable

Re: Queues just aren't scalable

[Shark8]

On Tuesday, June 25, 2013 8:53:03 AM UTC-6, aminer wrote:
> 
> Queues just aren't scalable
> 

> Read this:
> http://concurrencyfreaks.blogspot.ca/2013_05_01_archive.html


...isn't that obvious?
A Queue, like a Stack, has implicit sequentiality -- anyone who's had to wait for someone else to get their plate from an all-you-can-eat buffet plate-stack has experienced this... anyone who has waited in line at the DMV has experienced this.

Re: Queues just aren't scalable

[Dmitry A. Kazakov]

On Tue, 25 Jun 2013 15:34:28 -0700 (PDT), Shark8 wrote:

> On Tuesday, June 25, 2013 8:53:03 AM UTC-6, aminer wrote:
>> 
>> Queues just aren't scalable
> 
>> Read this:
>> http://concurrencyfreaks.blogspot.ca/2013_05_01_archive.html
> 
> ...isn't that obvious?

No, it is not. There is no obvious reason why the *same* number requests
submitted by one thread should be processed substantially slower when
submitted by several threads.

Let us ignore for a while that peer-to-peer (1-to-1) queues can be
implemented differently (e.g. without locking) than n-to-1 queues.

> A Queue, like a Stack, has implicit sequentiality -- anyone who's had to
> wait for someone else to get their plate from an all-you-can-eat buffet
> plate-stack has experienced this... anyone who has waited in line at the
> DMV has experienced this.

BTW, scalability is not what seems to be implied here. A system is scalable
in the parameter X and the outcome L if L depends on X more or less linear:

   L = a X + b

E.g.

X = number of threads
L = latency

Scalability does NOT mean that a = 0!

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de