There's memory bandwidth and there's memory transaction thruput

Pat Caudill patc at
Wed Feb 10 21:49:57 UTC 1999

>> There was a paper about this at ISMM '98 which preceeded the last OOPSLA. 
>> See the paper by Chilimbi and Larus. It worked well for C++ but not as 
>> well with Java because the larger object headers filled the cache lines 
>> as I remember.
>Given that Java object headers need only be two words long for many
>systems, how does this compare with C++, which often pays both a
>malloc overhead (depends on the allocator, it can be zero, but it
>is often two words) and a VTBL pointer overhead (at least one word,
>more if there is tricky inheritance going on)?

Oops, I rechecked the paper and the language was Cecil not C. I'll have 
to get my memory replaced I guess :-) The difference was between 1 word 
object headers and three word object headers for their system (again this 
is from my leaky memory) The results with Java are not in the paper but 
were mentioned, as preliminary, at the conference.

Pat Caudill
patc at

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