Date: Tue, 30 Jan 1996 17:47:25 +1000 (AEST) From: Greg Ungerer <gerg@stallion.oz.au> To: Bruce Evans <bde@zeta.org.au> Cc: gerg@stallion.oz.au, hackers@freebsd.org Subject: Re: Multi-Port Async Cards Message-ID: <9601301747.aa25485@cluster.stallion.oz.au> In-Reply-To: <199601300651.RAA26258@godzilla.zeta.org.au> from "Bruce Evans" at Jan 30, 96 05:51:55 pm
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Bruce Evans writes: > >Let me back this up with some numbers, a Stallion EasyConnection 8/64 ISA > >(which is powered by a 25MHz 186 with 512K RAM) uses about 0.1% host CPU > >per kbyte output (test done on a commercial UNIX flavor, Pentium 90, > >32M RAM). The EISA bus version of the board does even better (32 bit writes > >of data sure help). > > For comparison, a Cyclades 8Yo ISA uses about 0.4% host CPU per kbyte > output in opost mode (test done on FreeBSD-current, 486DX/33, 8MB RAM). > Why is the Stallion so slow? :-). The Cyclades board "intelligent" but Hmmm, comparing apples and oranges to some extent. As I pointed out this bench mark result was done on a comercial UNIX flavor, I expect the above number was done on a FreeBSD system? Also the above test was done with 32 ports attached to the board, if only 1 8-port unit was attached there would be measurably lower host overhead again (due to the sigificantly larger shared memory buffers). > essentially none of the intelligence is used since it would make little > difference. The overhead is half for ISA bus accesses (only about 1/4 > for interrupts). That's why the Stallion/P90 isn't much faster. Other > numbers: Sure the ISA bus only goes so fast. And you can't do much about that, except off-course switch to using a better bus... > > as above, -opost mode 0.3%/KB > > 16550, 486DX2/66, -opost 0.25% (one port) > 16450, 486DX2/66, -opost 1.1% > 16450, 386/20, -opost 3.7% > > A 16550 is slightly faster than a cd1400 but the FreeBSD-current > multiplexing code is more general and slower for 16550 multiport boards > than for 8Yo's. > > Linux Comtrol Rocketport driver as reported in Linux Journal: > > 486DX/33, -opost 0.08% > 486DX/33, opost 0.77% Again, different OS and different number of ports. It does make a difference... The only fair comparison is all boards similarly configured, in the same system, running the same OS... > > The RocketPort is faster mainly because it provides 16 bit i/o's and larger > FIFOs. > > I'd like to see some numbers for terminal servers. The FreeBSD pty > overhead is 10 times larger than the serial overhead in some cases. > I'm not sure if these cases are used with terminal servers. For > rlogin over ethernet, `dd if=/dev/zero bs=8k' consumes 100% of my > 486DX/33 and has a transfer speed 87381 bytes/sec (whee :-() > > 486DX/33, NE2000, opost 1.17%/KB (96.3%Sys 3.2%%Intr 0.5%User) > > The nulls in the output exercise the slowest parts of the opost code; > catting normal text files is about 5 times faster. The other benchmarks > transmit normal text files; otherwise their opost overheads would be > higher. Intelligent cards might help here, but so would better opost > code, and sending all nulls is unusual. > It would be interresting to compare... Seeya Gerg --------------------------------------------------------------------------- Greg Ungerer EMAIL: gerg@stallion.com Stallion Technologies Pty Ltd PHONE: +61 7 3270 4271 33 Woodstock Rd, Toowong, QLD 4066, Australia FAX: +61 7 3270 4245
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