Speeding up Unix

[Doug Gwyn (VLD/VMB)]

The exact tradeoffs depend on the specific hardware involved.  Here
are some ideas that should work especially well for smaller systems:

Item # 1:  Install the 3B20A semaphores in all UNIX kernels, so
that unnecessary lockout of interrupts does not occur.

Item # 2:  Fix the scheduler.

Item # 3:  Locate and fix all linear searches through tables that
might grow larger than a dozen or so entries.

Item # 4:  Install stream I/O.  This in itself may not speed things
up much, but it provides the base for moving functionality out of
the host CPU and into smart I/O processors (terminal driver in your
5620, anyone?).

Item # 5:  Do not resort to overly complicated algorithms; the CPU
is not a "free" resource.

Item # 6:  Start ripping stuff out of the kernel if it can be done
well in user mode with the support of a more general kernel facility.
The wasted memory reclaimed will improve performance of user processes.