CVS commit: src

[Bill Sommerfeld <sommerfeld%netbsd.org@localhost>]

Module Name:    src
Committed By:   sommerfeld
Date:           Mon Feb  8 07:05:51 UTC 1999

Modified Files:
        src/sys/dev/wscons: wsdisplay.c
Log Message:
Change WSDISPLAYBURST from OBUFSIZ-1 to OBUFSIZ*4, for a ~15x
improvement in the "cat /usr/share/misc/termcap" benchmark on 486/75

ttwrite queues data for us in OBUFSIZ chunks.  If we only consume
OBUFSIZ-1 bytes per call to wsdisplaystart(), we're *guaranteed* to
fall behind when given maximum-sized reads (which will defer
processing the leftovers until ttrstrt gets called, after a timeout)

Note that OBUFSIZ*4 may be overkill; OBUFSIZ*3 may be sufficient to
get maximal performance; OBUFSIZ*2 resulted in only about a 2.5x
performance improvement, but it's 2am and I've done enough tweaking
for the night.