From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S270121AbTGUOVh (ORCPT ); Mon, 21 Jul 2003 10:21:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S270122AbTGUOVh (ORCPT ); Mon, 21 Jul 2003 10:21:37 -0400 Received: from chaos.analogic.com ([204.178.40.224]:28035 "EHLO chaos.analogic.com") by vger.kernel.org with ESMTP id S270121AbTGUOVe (ORCPT ); Mon, 21 Jul 2003 10:21:34 -0400 Date: Mon, 21 Jul 2003 10:38:38 -0400 (EDT) From: "Richard B. Johnson" X-X-Sender: root@chaos Reply-To: root@chaos.analogic.com To: "Ihar \"Philips\" Filipau" cc: linux-kernel@vger.kernel.org Subject: Re: SVR4 STREAMS (for example LiS) In-Reply-To: <3F1BF509.1000608@giga-stream.de> Message-ID: References: <3F1BF509.1000608@giga-stream.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 21 Jul 2003, Ihar "Philips" Filipau wrote: > Hello All! > > I have little bit theoretical question. As usual ;-) > > From what ever piece of doc I see says that STREAMS are good. > They are part of SUS (at least v3 has them). > Sun's docs reffering only cases when one may want to use them. > This was the first pointer to problems: docs are missing the > "dark side" of STREAMS. > > Can anyone give any pointers to information why STREAMS are _not_ > part of Linux kernel yet? > (Besides that no-one needs/merged it in kernel ;-) > What kind of problems this implementation of I/O has? > (Low performance and high latencies I expect - but what's else?) > > Any sort of RTFM will be very appreciated. > > Thanks in advance. > Streams are an extension of buffered I/O implimented by the 'C' runtime library. Streams really have nothing to do with the internal workings of kernel I/O. As far as kernel I/O goes, one reads() and writes() from user-space. That said, the kernel provides getpmsg and putpmsg functions to support streams. You really can't do much more for streams inside the kernel and be efficient. Cheers, Dick Johnson Penguin : Linux version 2.4.20 on an i686 machine (797.90 BogoMips). Note 96.31% of all statistics are fiction.