Messages in this thread | | | Date | Fri, 23 Feb 2007 09:43:14 -0800 (PST) | From | Davide Libenzi <> | Subject | Re: [patch 00/13] Syslets, "Threadlets", generic AIO support, v3 |
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On Fri, 23 Feb 2007, Evgeniy Polyakov wrote:
> On Thu, Feb 22, 2007 at 11:46:48AM -0800, Davide Libenzi (davidel@xmailserver.org) wrote: > > > > A dynamic pool will smooth thread creation/freeing up by a lot. > > And, in my box a *pthread* create/free takes ~10us, at 1000/s is 10ms, 1%. > > Bad, but not so aweful ;) > > Look, I'm *definitely* not trying to advocate the use of async syscalls for > > network here, just pointing out that when we're talking about threads, > > Linux does a pretty good job. > > If we are going to create 1000 threads each second, then it is better to > preallocate them and queue a work to that pool - like syslets did with > syscalls, but not ulitimately create a new thread just because it is not > that slow.
We do create a pool indeed, as I said in the opening of my asnwer. The numbers I posted was just to show that thread creation/destroy is pretty fast, but that does not justify it as a design choice.
> All such micro-thread designs are especially good in the case when > 1. switching is _rare_ (very) > 2. programmer does not want to create complex model to achieve maximum > performance > > Disk (cached) IO definitely hits first entry and second one is there for > advertisements and fast deployment, but overall usage of the > asynchronous IO model is not limited to the above scenario, so > micro-threads definitely hit own niche, but they can not cover all usage > cases.
You know, I read this a few times, but I still don't get what your point is here ;) Are you talking about micro-thread design in the kernel as for kthreads usage for AIO, or about userspace?
- Davide
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