From owner-freebsd-questions Thu Oct 19 15:05:32 1995 Return-Path: owner-questions Received: (from root@localhost) by freefall.freebsd.org (8.6.12/8.6.6) id PAA03682 for questions-outgoing; Thu, 19 Oct 1995 15:05:32 -0700 Received: from chrome.jdl.com (chrome.onramp.net [199.1.166.202]) by freefall.freebsd.org (8.6.12/8.6.6) with ESMTP id PAA03672 for ; Thu, 19 Oct 1995 15:05:26 -0700 Received: from localhost.jdl.com (localhost.jdl.com [127.0.0.1]) by chrome.jdl.com (8.6.11/8.6.9) with SMTP id RAA15051; Thu, 19 Oct 1995 17:05:20 -0500 Message-Id: <199510192205.RAA15051@chrome.jdl.com> X-Authentication-Warning: chrome.jdl.com: Host localhost.jdl.com didn't use HELO protocol To: davidg@Root.COM cc: questions@freebsd.org Subject: Slow throughput In-reply-to: Your message of "Thu, 19 Oct 1995 13:07:20 PDT." <199510192007.NAA29801@corbin.Root.COM> Reply-To: jdl@chromatic.com Clarity-Index: null Threat-Level: none Software-Engineering-Dead-Seriousness: There's no excuse for unreadable code. Net-thought: If you meet the Buddha on the net, put him in your Kill file. Date: Thu, 19 Oct 1995 17:05:19 -0500 From: Jon Loeliger Sender: owner-questions@freebsd.org Precedence: bulk [Moved to questions from hackers] Apparently, David Greenman scribbled: > Let me add a bit of sanity to this part of the discussion. 115200 baud async > will give you about 11.52Kbytes/second if you have no packet overhead. 115200 > baud sync will give you 14.40Kbytes/second if you have no packet overhead. > Why? Because we're talking bits - async is 8 data bits plus 1 start and 1 > stop bit...10 bits. With synchronous serial, it's just 8 data bits. So sync > always has the potential to give you 25% more bytes throughput at the same > bit rate compared to async. > Now with sync you'll also be running at a faster bit rate (128000bits/sec). > This is 16Kbytes/second. This is 38.9% faster. OK, it's pretty clear now that I might have a mysteriously slow component to my system's network (?) throughput. How do I find it? I've got ISDN, usually at 64kb/sec but BOND-able to 128kb/sec connected to a pipeline-50 which is spewing ethernet to a 10BaseT hub. My machine is on the hub with one other machine now. I've got a Linksys Ether 16 NE2000 card hanging off the ISA bus. At 64k ftp suggests a sustained rate of about: 41539 bytes received in 23 seconds (1.8 Kbytes/s) 1936621 bytes received in 8.9e+02 seconds (2.1 Kbytes/s) It is somewhat slow, isn't it? What's the slow part of this equation? ISDN, P-50, ether, ISA, or writing to my IDE disks (WD 31000)? I suspect that the ether card on the ISA bus is the slow part here. However, when I get a 128k line, I *do* get about 4k/sec throughput. Does this fact alone point at, like, the IDE disk. How can I find out? Ie, which performance monitoring tool or benchmark should I run to really place the blame? :-) What piece of this picture should I replace first? If I wanted to improve things, and was thinking about a PCI SCSI card anyways (tape backup), what might I do? (I also have a 3Com Etherlink III lovely 3c509B on hand too.) Thanks, jdl