Date: Thu, 05 Mar 1998 14:16:45 +1100 From: John Saunders <john.saunders@scitec.com.au> To: shimon@simon-shapiro.org, freebsd-current@FreeBSD.ORG Subject: Re: silo overflows (Was Re: 3.0-RELEASE?) Message-ID: <34FE191D.1D676AC3@scitec.com.au> References: <XFMail.980304185844.shimon@simon-shapiro.org>
next in thread | previous in thread | raw e-mail | index | archive | help
Simon Shapiro wrote:
> [snip] Every 1KB, you write to disk [snip]
If you use an IDE disk then 10 to 1 that's the problem. Particularly
if the IDE driver is doing multi-sector transfers. Interrupts must be
disabled during IDE PIO transfers (or you can risk data corruption)
and the time taken to transfer, say 16 sectors, is significant. When
Linux supported Intel Triton busmaster IDE the occurance of FIFO
overflows disappeared on Triton boards.
For example I can run 6 16550 ports under Linux using busmaster
support without any FIFO overflows. However I have trouble running 2
at 57600 bps without FIFO overflows.
The solution is to use either a SCSI disk system, or support
busmastering IDE. The real problem is the crazy IRQ priorities of
the PC architeture.
Cheers.
-- +------------------------------------------------------------+
. | John Saunders mailto:John.Saunders@scitec.com.au (Work) |
,--_|\ | mailto:john@nlc.net.au (Home) |
/ Oz \ | http://www.nlc.net.au/~john/ |
\_,--\_/ | SCITEC LIMITED Phone +61 2 9428 9563 Fax +61 2 9428 9933 |
v | "By the time you make ends meet, they move the ends." |
+------------------------------------------------------------+
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-current" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?34FE191D.1D676AC3>