[Tcl-bugs] [ tcl-Patches-1772004 ] objReform

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Patches item #1772004, was opened at 2007-08-10 18:43
Message generated for change (Comment added) made by msofer
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Category: 10. Objects
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: miguel sofer (msofer)
Assigned to: miguel sofer (msofer)
Summary: objReform

Initial Comment:
(all numbers on 32 b systems)

A Tcl_Obj requires 24 bytes, a typical cache line fits 32 bytes. This means that about half the Tcl_Objs will occupy a single cache line, half will require two.

Adding 8 bytes at the end of a Tcl_Obj insures that all Tcl_Obj are cache-aligned. The additional space can be used to store the stringRep for small strings, saving the alloc/free.

Attached a proof-of-concept patch (hard wired for 32b, for 64b 16 bytes should be added).

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>Comment By: miguel sofer (msofer)
Date: 2007-08-10 20:52

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pat thoyts produced initial benchmarks:
http://www.patthoyts.tk/benchmarks.html

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You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=310894&aid=1772004&group_id=10894