[comp.arch] Sun4 caches?

prl@iis.ethz.ch (Peter Lamb) (04/23/91)

I would appreciate it if someone could send me a short summary
(or a pointer to one on anon FTP) of the cache structure for Sun4's
(especially SparcStations).

I have a performance problem which may be cache-related, and I need
to know a little more than I would otherwise care about the caches.

I/D separation, line width, virtual/physical address tags, mapping
from address into cache line address, replacement strategy if not one-way,
etc.

Thanks in advance,

--
Peter Lamb
uucp:  uunet!mcsun!ethz!prl	eunet: prl@iis.ethz.ch	Tel:   +411 256 5241
Integrated Systems Laboratory
ETH-Zentrum, 8092 Zurich

mark@hubcap.clemson.edu (Mark Smotherman) (04/23/91)

From article <prl.672351796@iis>, by prl@iis.ethz.ch (Peter Lamb):
> I would appreciate it if someone could send me a short summary
> of the cache structure for Sun4's (especially SparcStations).

SPARCstation 1 (SS1):

IU     - LSI Logic L64801
FPU    - Weitek WTL3170
clock  - 20 MHz
cache  - combined I+D, 64Kb, virtually addressed with OS-managed alias
         avoidance, 16-byte lines, direct mapped, write through, no write
         allocate on write miss, no read through on read miss, 32-bit
         bus from memory to cache, 32-bit bus from cache to processor
memory - 2-cycle load, 3-cycle store, 11-cycle cache refill
buffer - 1-word write buffer in cache (double-word stores stall)

(From: A.V. Bechtolsheim and E.H. Frank, "Sun's SPARCstation 1: A
Workstation for the 1990s," IEEE Spring Compcon, San Francisco,
Feb.-March 1990, pp. 184-188.)

I believe that the information above also holds for the SS1+, with the
exception that the clock rate is 25 MHz.

Would someone from Sun please confirm the above and give a similar
description for the SS2?  Thanks.

-- 
Mark Smotherman, CS Dept., Clemson University, Clemson, SC 29634-1906
                 mark@cs.clemson.edu  or  mark@hubcap.clemson.edu