[comp.sys.ibm.pc.misc] Disk Cache Measurements - Part III

reisert@ricks.enet.dec.com (Jim Reisert) (08/22/90)

Here are the results of the last set of measurements I have done.  They
attempt to measure the following effects:

	* P.R. Glassel & Assoc., Inc. QCACHE 4.20
	* BUFFERS=4 vs. BUFFERS=16
	* when running under Quarterdeck's DESQview
	* as measured by Multisoft's PC-Kwik benchmark

NOTE: I attempted to measure the performance of HYPERDRIVE, but the
      shareware copy I was to test did not have all the features enabled,
      such as write buffering, so I didn't test it.

1.  Measurement of P.R. Glassel & Assoc., Inc. QCACHE 4.20

Here is how QCACHE compared to other disk caches as measured with the PC
Labs Benchmark 5.0 (the tests are described at the end).  The cache size in
all cases was 384K, and QCACHE performed identically in conventional and
expanded memory:

		TEST1	TEST2	TEST3	TEST4

no cache	58.50	8.86	5.44	3.99	secs.
SMARTDRV	35.06	7.26	4.00	3.33	 "
PC-CACHE 5.5	30.29	6.70	3.73	3.32	 "
PC-CACHE 6.03	13.13	8.53	3.14	2.75	 "
QCACHE 4.20	 9.87	9.18	3.96	3.65	 "
SuperPCK 3.56	 8.52	4.94	1.83	2.45	 "

2.  Effect of BUFFERS

I ran the PC Labs Benchmark tests (described below).  The first run had
BUFFERS=4 and the second had BUFFERS=16:

BUFFERS=4	TEST1	TEST2	TEST3	TEST4

no cache	58.50	8.86	5.44	3.99	secs.
SuperPCK 3.56	 8.52	4.94	1.83	2.45	 "

BUFFERS=16	TEST1	TEST2	TEST3	TEST4

no cache	58.05	8.82	4.92	4.06	secs.
SuperPCK 3.56	 8.64	4.91	2.63	2.44	 "

The setting of BUFFERS seemed to have no effect, except in TEST3 (see
description below).

3.  Running under DESQview

Here are the results of running with three different caches, using a single
512K DOS window in DESQview.  The results of running with cache in expanded
or extended memory are the same:

		TEST1	TEST2	TEST3	TEST4

no cache	69.79	12.05	10.95	10.63	secs.
PC-CACHE 5.5	31.61	 7.61	 5.13	 4.56	 "
PC-CACHE 6.03	16.05	12.24	10.47	10.24	 "
SuperPCK 3.56	32.54	 8.26	 5.32	 4.97	 "

For comparison, here are the same tests, run in stand-alone mode:

		TEST1	TEST2	TEST3	TEST4

no cache	58.50	8.86	5.44	3.99	secs.
PC-CACHE 5.5	30.29	6.70	3.73	3.32	 "
PC-CACHE 6.03	13.13	8.53	3.14	2.75	 "
SuperPCK 3.56	 8.52	4.94	1.83	2.45	 "

4.  PC-Kwik Benchmark

Multisoft provides a disk cache benchmarking package with their Power Pack
(Does it come with Super PC-Kwik also?).  Their benchmark runs two tests:
512 records of 512 bytes, and 64 records of 4096 bytes.

Here are the results of using a 384K disk cache in expanded memory:

		TEST1	TEST2

no cache	54.10	8.79	secs.
SMARTDRV	31.75	6.87	  "
PC-CACHE 5.5	29.39	5.82	  "
SuperPCK 3.56	13.46	4.94	  "
PC-CACHE 6.03	 3.68	6.59	  "

Here are the results of using a 384K disk cache in extended memory:

		TEST1	TEST2

no cache	54.10	8.79	secs.
SMARTDRV	30.65	6.76	  "
PC-CACHE 5.5	29.49	5.88	  "
SuperPCK 3.56	11.50	6.18	  "
PC-CACHE 6.03	13.51	5.99

The results are almost identical, except PC-CACHE 6.03 and SuperPCK 3.56
both seemed to perform worse in extended memory.

I think I have satisfied everyone's requests for measurements.  If not,
please let me know.

jim

DESCRIPTION of SYSTEM and TESTS:

All tests were run on a 20 MHz 386 machine with a 42 MB hard disk (that was
defragmented at the end of each test) and 2 MB RAM running MS-DOS 4.01.  I
used QEMM as my EXPAnded memory manager.  All tests were run at the DOS
prompt (as opposed to under Windows or DESQview), unless otherwise noted.

The following tests comprise the PC-Labs Benchmark Test 5.0 suite:

	TEST1 - 512 records of   512 bytes each
	TEST2 -  64 records of  4096 bytes each
	TEST3 -  16 records of 16384 bytes each
	TEST4 -   8 records of 32768 bytes each

Each test had 5 stages: 1) file creation, 2) sequential write, 3) sequential
read, 4) random write and 5) random read.  The results are listed in
seconds.

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"The opinions expressed here in no way represent the views of Digital
 Equipment Corporation."

James J. Reisert                Internet: reisert@ricks.enet.dec.com
Digital Equipment Corp.         UUCP:     ...decwrl!ricks.enet!reisert
77 Reed Road
Hudson, MA  01749-2895