OpenSolaris

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Bug ID 6340196
Synopsis Probe effect when using strings in aggregations could be reduced
State 10-Fix Delivered (Fix available in build)
Category:Subcategory kernel:dtrace
Keywords aggregation | effect | probe | string
Responsible Engineer Bryan Cantrill
Reported Against
Duplicate Of
Introduced In
Commit to Fix snv_30
Fixed In snv_30
Release Fixed solaris_nevada(snv_30) , solaris_10u4(s10u4_03) (Bug ID:2139203)
Related Bugs
Submit Date 21-October-2005
Last Update Date 16-February-2007
Description
DTrace uses the Bob Jenkins "One-at-a-time" hashing algorithm to hash the keys in an aggregation. Whilst being an excellent algrorithm, it's additive nature can be expensive when used with large objects such as D Strings. D Strings are, by default, 256 bytes long and are often used in aggregations to store short strings such as a function or module name. Iterating over all 256 bytes to generate a hash value can be expensive and therefore introduces a non trivial probe effect. Any reduction in probe effect would be good.

See comments.
Work Around
N/A
Comments
N/A