Re: JavaMemoryModel: Summary of useless sync

From: David F. Bacon (dfb@watson.ibm.com)
Date: Mon Nov 15 1999 - 09:26:14 EST


> Vector 61,984,740 69.6%
> BufferedInputStream 8,941,342 10.0%
> HashTable 8,278,439 9.3%
> BufferedOutputStream 4,376,207 4.9%
> ByteArrayOutputStream 3,831,749 4.3%

bill,

we got similar numbers when we did our measurements for thin locks: vector, the
various streams, hashtable, bitset, and stringbuffer accounted for essentially
all of the synchronizations. the real laugher was jax, which did 19 million
synchronized bitset operations.

> String 688,315 0.8%

i don't understand why string is on that list though. string is immutable, and
requires no synchronization, no?

david

p.s. the thin locks paper is available at

  http://www.research.ibm.com/people/d/dfb/papers.html#Bacon98Thin

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