Path: utzoo!dptcdc!jarvis.csri.toronto.edu!mailrus!shadooby!accuvax.nwu.edu!tank!ncar!umigw!umbio!medsoft!f6.n135.z1.fidonet.org!Ed.Maurer From: Ed.Maurer@f6.n135.z1.fidonet.org (Ed Maurer) Newsgroups: comp.sys.ibm.pc Subject: Cache & Buffers..how many buffers are required? Message-ID: <275.244AB1AD@medsoft.uucp> Date: 18 Apr 89 04:10:00 GMT Sender: ufgate@medsoft.uucp (newsout1.18) Organization: FidoNet node 1:135/6 Lines: 71 > Can anybody offer some insight? I have been told that if you > use a disk caching program then you can reduce the number of buffers > specified in the `Buffers= ' entry in config.sys. > Question: By how much can you reduce the number? Is there > any way of optimizing' the number of buffers? You are correct to assume that you should decrease the buffer size when using a cache, but not down as far as you might think. I'm attaching the following test run on my 386 with ESDI 44Mb Disk. Note that under all cache conditions, optimum buffers is between 13-16. Without a cache, optimum buffer size appears to be around 40. This is, of course, one test, (write 1000 1K records, swap and shuffle records); but the results are in general agreement with other published data. The PD program 'Thrasher' was used to create the following table: TIMES IN SECONDS COMPAQ DISK CACHE MicroSoft MicroSoft No Cache 256K 128K 256K in ext mem in ext mem in ext mem ---------------- --------------- --------------- -------------- BUFFERS=05= 8 BUFFERS=05= 26 BUFFERS=05= 25 BUFFERS=10= 33 BUFFERS=06= 7 BUFFERS=06= 23 BUFFERS=06= 21 BUFFERS=11= 34 BUFFERS=07= 7 BUFFERS=07= 20 BUFFERS=07= 19 BUFFERS=12= 34 BUFFERS=08= 5 BUFFERS=08= 15 BUFFERS=08= 14 BUFFERS=13= 33 BUFFERS=09= 5 BUFFERS=09= 12 BUFFERS=09= 11 BUFFERS=14= 33 BUFFERS=10= 5 BUFFERS=10= 12 BUFFERS=10= 11 BUFFERS=15= 33 BUFFERS=11= 5 BUFFERS=11= 12 BUFFERS=11= 11 BUFFERS=16= 33 BUFFERS=12= 5 BUFFERS=12= 12 BUFFERS=12= 11 BUFFERS=17= 33 BUFFERS=13= 4 BUFFERS=13= 12 BUFFERS=13= 11 BUFFERS=18= 34 BUFFERS=14= 4 BUFFERS=14= 12 BUFFERS=14= 11 BUFFERS=19= 33 BUFFERS=15= 5 BUFFERS=15= 12 BUFFERS=15= 11 BUFFERS=20= 32 BUFFERS=16= 5 BUFFERS=16= 12 BUFFERS=16= 11 BUFFERS=21= 33 BUFFERS=17= 5 BUFFERS=17= 12 BUFFERS=17= 11 BUFFERS=22= 32 BUFFERS=18= 5 BUFFERS=18= 12 BUFFERS=18= 11 BUFFERS=23= 32 BUFFERS=19= 5 BUFFERS=19= 12 BUFFERS=19= 12 BUFFERS=24= 32 BUFFERS=20= 5 BUFFERS=20= 12 BUFFERS=20= 11 BUFFERS=25= 33 BUFFERS=21= 5 BUFFERS=21= 13 BUFFERS=21= 12 BUFFERS=26= 33 BUFFERS=22= 5 BUFFERS=22= 13 BUFFERS=22= 11 BUFFERS=27= 33 BUFFERS=23= 5 BUFFERS=23= 13 BUFFERS=23= 12 BUFFERS=28= 33 BUFFERS=24= 5 BUFFERS=24= 13 BUFFERS=24= 13 BUFFERS=29= 33 BUFFERS=25= 5 BUFFERS=25= 13 BUFFERS=25= 12 BUFFERS=30= 33 BUFFERS=26= 5 BUFFERS=26= 13 BUFFERS=26= 11 BUFFERS=31= 33 BUFFERS=27= 5 BUFFERS=27= 13 BUFFERS=27= 12 BUFFERS=32= 33 BUFFERS=28= 5 BUFFERS=28= 13 BUFFERS=28= 12 BUFFERS=33= 33 BUFFERS=29= 5 BUFFERS=29= 14 BUFFERS=29= 12 BUFFERS=34= 33 BUFFERS=30= 5 BUFFERS=30= 14 BUFFERS=30= 14 BUFFERS=35= 33 BUFFERS=31= 5 BUFFERS=31= 14 BUFFERS=31= 14 BUFFERS=36= 33 BUFFERS=32= 5 BUFFERS=32= 14 BUFFERS=32= 14 BUFFERS=37= 33 BUFFERS=33= 6 BUFFERS=33= 15 BUFFERS=33= 15 BUFFERS=38= 33 BUFFERS=34= 6 BUFFERS=34= 14 BUFFERS=34= 14 BUFFERS=39= 31 BUFFERS=35= 6 BUFFERS=35= 14 BUFFERS=35= 14 BUFFERS=40= 32 BUFFERS=36= 6 BUFFERS=36= 15 BUFFERS=36= 15 BUFFERS=41= 32 BUFFERS=37= 7 BUFFERS=37= 14 BUFFERS=37= 16 BUFFERS=42= 33 BUFFERS=38= 7 BUFFERS=38= 14 BUFFERS=38= 16 BUFFERS=43= 32 BUFFERS=39= 8 BUFFERS=39= 17 BUFFERS=39= 17 BUFFERS=44= 34 BUFFERS=40= 8 BUFFERS=40= 18 BUFFERS=40= 17 BUFFERS=45= 33 \\\\\\ ] \^ \\\\\\\\ ]x ]^ Maurer ^ The Micro Group, Inc., Pembroke Pines, FL ___ ___________ (Never replicate a successful test) (....But it worked fine yesterday!) -- Ed Maurer - via FidoNet node 1:135/3 Medical Software Exchange BBS (305) 325-8709 UUCP: ...uunet!gould!umbio!medsoft!6!Ed.Maurer ARPA: Ed.Maurer@f6.n135.z1.fidonet.org