Re: [patch 00/13] Syslets, "Threadlets", generic AIO support, v3

Ingo Molnar
2007-02-22T15:04:37Z

* Ingo Molnar <mingo@elte.hu> wrote:

> Firstly, i dont think you are fully applying the syslet/threadlet
> model. There is no reason why an 'idle' client would have to use up a
> full thread! It all depends on how you use syslets/threadlets, and how
> (frequently) you queue back requests from cachemiss threads back to
> the primary thread. It is only the simplest queueing model where there
> is one thread per request that is currently blocked.
> Syslets/threadlets do /not/ force request processing to be performed
> in the async context forever - the async thread could very much queue
> it back to the primary context. (That's in essence what Tux did.) So
> the same state-machine techniques can be applied on both the syslet
> and the threadlet model, but in much more natural (and thus lower
> overhead) points: /between/ system calls and not in the middle of
> them. There are a number of measures that can be used to keep the
> number of parallel threads down.

i think the best model here is to use kevents or epoll to discover
accept()-able or recv()-able keepalive sockets, and to do the main
request loop via syslets/threadlets, with a 'queue back to the main
context if we went async and if the request is done' feedback mechanism
that keeps the size of the pool down.

Ingo