From owner-freebsd-hackers  Tue Apr 14 04:50:09 1998
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To: hackers@FreeBSD.ORG
cc: smp@FreeBSD.ORG
Subject: SMP performance decrease?
Reply-To: tarkhil@asteroid.svib.ru
Date: Tue, 14 Apr 1998 15:49:35 +0400
From: "Alexander B. Povolotsky" <root@asteroid.svib.ru>
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Hello!

I've just benchmarked (by bytebench from ports) my new server, with 64M RAM
(for now; will increase soon) and 2 PII-233 processors (EliteGroup p6LX2-A
mainboard).

Here are the results:

Test                            Non-SMP      SMP
arith (double)                   27.5        28.1 
Drystone 2 (no reg. vars)        23.6        24.1
Execl thoughput                  90.8        46.8   <- ??? 
File copy                        35.1        37.7   
Pipe-based context switching     20.4         9.0   <- ???
Shell scripts (8 concurrent)     12.8        12.2   <- ???

I don't understand why execl throughput and context switching is TWICE 
slower in SMP mode, and I doesn't understand AT ALL why shell script 
benchmark isn't twice faster.

Wrong benchmark? Problems with something in kernel? Me being crazy?

Alex.


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