Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 18 Jun 2002 17:20:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 18 Jun 2002 17:20:12 -0400 Received: from hq.fsmlabs.com ([209.155.42.197]:44551 "EHLO hq.fsmlabs.com") by vger.kernel.org with ESMTP id ; Tue, 18 Jun 2002 17:20:11 -0400 From: Cort Dougan Date: Tue, 18 Jun 2002 15:08:40 -0600 To: Benjamin LaHaise Cc: Linus Torvalds , Rusty Russell , Robert Love , Linux Kernel Mailing List Subject: Re: latest linus-2.5 BK broken Message-ID: <20020618150840.Q13770@host110.fsmlabs.com> References:

<20020618171200.G16091@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20020618171200.G16091@redhat.com>; from bcrl@redhat.com on Tue, Jun 18, 2002 at 05:12:00PM -0400 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1656 Lines: 33 I agree with you there. It's not easy, and I'd claim it's not possible given that no-one has done it yet, to have a select() call that is speedy for both 0-10 and 1k file descriptors. } I take issue with the statement that select scales fine to thousands of } file descriptors. It doesn't. For fairly trivial workloads it degrades } to 0 operations per second with more than a few dozen filedescriptors in } the array, but only one descriptor being active. To sustain decent } throughput, select needs something like 50% of the filedescriptors in an } array to be active at every select() call, which makes in unsuitable for } things like LDAP servers, or HTTP/FTP where the clients are behind slow } connections or interactive (like in the real world). I've benchmarked } it -- we should really include something like /dev/epoll in the kernel } to improve this case. } } Still, I think the bitmap approach in this case is useful, as having } affinity to multiple CPUs can be needed, and it is not a frequently } occuring operation (unlike select()). } } -ben } -- } "You will be reincarnated as a toad; and you will be much happier." } - } To unsubscribe from this list: send the line "unsubscribe linux-kernel" in } the body of a message to majordomo@vger.kernel.org } More majordomo info at http://vger.kernel.org/majordomo-info.html } Please read the FAQ at http://www.tux.org/lkml/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/