Path: utzoo!utgpu!water!watmath!clyde!rutgers!sri-spam!ames!elroy!cit-vax!mangler From: mangler@cit-vax.Caltech.Edu (Don Speck) Newsgroups: comp.unix.wizards Subject: Re: rdump, Ethernet slowness Summary: tcp throughput should be higher Message-ID: <4835@cit-vax.Caltech.Edu> Date: 10 Dec 87 08:47:04 GMT References: <788@hsi.UUCP> <1268@laidbak.UUCP> Organization: California Institute of Technology Lines: 19 In article <1268@laidbak.UUCP>, mdb@laidbak.UUCP (Mark Brukhartz) writes: > I believe that the /etc/rmt protocol, used by rdump, is synchronous. Each > I/O operation is acknowledged (back through the Ethernet) before the next > one is begun. That wasn't the bottleneck. The problem lies in this section: In article <788@hsi.UUCP>, stevens@hsi.UUCP (Richard Stevens) writes: > 52,000 bytes/sec - speed of a C program writing 1000 32768-byte > buffers to another process on the other system, > across the Ethernet, using a stream socket, as > in the 552,000 bytes/sec example given above. 52Kbytes/sec of tcp throughput is ATROCIOUS for a VAX/785 with a good Ethernet board like an Interlan NI1010A. My 750's, with the same kind of Ethernet board, do 88 Kbytes/sec with reads of that size. I cannot account for why his throughput would be this poor. Any ideas? Don Speck speck@vlsi.caltech.edu {amdahl,scgvaxd}!cit-vax!speck