MPS issue job003778

TitleSegCheck slow in hot variety
Assigned userDavid Lovemore
DescriptionSegCheck gets called a lot, and is slow even in the hot variety.
AnalysisSegCheck ought to compile down to just a signature check, but it contains a loop over tracts of the segment that doesn't get compiled out (on windows) (even though the body does get compiled out) and dominates the run-time of the function. SegCheck contributes to about 1% of the run-time when measured on CET on the HOT variety.

I think the sensible thing is to only include the loop if CHECKLEVEL > CheckLevelMINIMAL

This seems to produce a 1% speed up.
How foundunknown
EvidenceProfiling CET.
Created byDavid Lovemore
Created on2014-04-30 16:29:06
Last modified byGareth Rees
Last modified on2014-05-10 09:44:25
History2014-04-30 DL Created
2014-05-06 DL Added solution to analysis


Change Effect Date User Description
185992 closed 2014-05-10 09:44:25 Gareth Rees Fix compilation of seg.c.
1. "#ifdef CHECKLEVEL > CheckLevelMINIMAL" was bogus: the #ifdef should have been #if, but even then it would not be right, because in the CHECKLEVEL_DYNAMIC configuration, CHECKLEVEL is a variable rather than a preprocessor constant. So use the condition defined(AVER_AND_CHECK_ALL) instead.
2. The final CHECKL(addr == seg->limit) only makes sense if the loop was executed.
3. The variables used by the loop need to be inside the #if to avoid warnings about unused variables.
4. Add reference to the job from a comment.
185971 closed 2014-05-06 12:19:06 David Lovemore Only include tract loop ion SegCheck when check level > minimal.
This is to speed up SegCheck in HOT variety.