Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: debate on 700 threads vs asynchronous code | From | Terje Eggestad <> | Date | 30 Jan 2003 10:36:24 +0100 |
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On ons, 2003-01-29 at 18:26, Lee Chin wrote: > Today I do method (C)... but many people seem to say that, hey, > pthreads does almost just that with a constant memory overhead of > remembering the stack per blocking thread... so there is no time > difference, just that pthreads consumes slightly more memory. That is > the issue I am trying to get my head around. > > That particular question, no one has answered... in Linux, the > scheduler will not go around crazy trying to schedule prcosses that > are all waiting on IO. NOw the only time I see a degrade in threads > would be if all are runnable.... in that case a async scheme with two > threads would let each task run to completion, not thrashing the > kernel. Is that correct to say?
Yes
And you can add that if you have many runnable threads, there will be an extra overhead doing context switching.
> ----- Original Message ----- > From: Terje Eggestad <terje.eggestad@scali.com> > Date: 27 Jan 2003 10:48:22 +0100 > To: Lee Chin <leechin@mail.com> > Subject: Re: debate on 700 threads vs asynchronous code > > > Apart from the argument already given on other replies, you should > > keep in mind that you probably need to give priority to doing receive. > > THat include your clients, but if you don't you run into the risk of > > significantly limiting your bandwidth since the send queues around your > > system fill up. > > > > Try doing that with threads. > > > > > > Actually I would recommend the approach c) > > > > c) Write an asynchronous system with only 2 or three threads where I > > manage the connections and keep the state of each connection in a data > > structure. > > > > > > On fre, 2003-01-24 at 00:19, Lee Chin wrote: > > > Hi > > > I am discussing with a few people on different approaches to solving a scale problem I am having, and have gotten vastly different views > > > > > > In a nutshell, as far as this debate is concerned, I can say I am writing a web server. > > > > > > Now, to cater to 700 clients, I can > > > a) launch 700 threads that each block on I/O to disk and to the client (in reading and writing on the socket) > > > > > > OR > > > > > > b) Write an asycnhrounous system with only 2 or three threads where I manage the connections and stack (via setcontext swapcontext etc), which is progromatically a little harder > > > > > > Which way will yeild me better performance, considerng both approaches are implemented optimally? > > > > > > Thanks > > > Lee > > -- > > _________________________________________________________________________ > > > > Terje Eggestad mailto:terje.eggestad@scali.no > > Scali Scalable Linux Systems http://www.scali.com > > > > Olaf Helsets Vei 6 tel: +47 22 62 89 61 (OFFICE) > > P.O.Box 150, Oppsal +47 975 31 574 (MOBILE) > > N-0619 Oslo fax: +47 22 62 89 51 > > NORWAY > > _________________________________________________________________________ > > -- _________________________________________________________________________
Terje Eggestad mailto:terje.eggestad@scali.no Scali Scalable Linux Systems http://www.scali.com
Olaf Helsets Vei 6 tel: +47 22 62 89 61 (OFFICE) P.O.Box 150, Oppsal +47 975 31 574 (MOBILE) N-0619 Oslo fax: +47 22 62 89 51 NORWAY _________________________________________________________________________
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