MPS issue job003921

TitleWrite barrier may be harmful to performance
Assigned userGareth Rees
DescriptionThe write barrier has positive and negative impacts on performamce. Positive: it allows the MPS to maintain a remembered set for a segment and so avoid scanning it. Negative: it incurs a barrier hit every time there is a write. The MPS has been written under the assumption that the positive outweighs the negative. But for segments with frequent writes this may be a false assumption: it might be better to drop the write barrier and pay the cost of always scanning it.
AnalysisThe MPS could spot the bad cases, and drop the write barrier. See changes [1] and [2].
How foundcustomer
Evidence[1] <>
[2] <>
Created byGareth Rees
Created on2015-08-05 14:00:58
Last modified byGareth Rees
Last modified on2015-08-05 14:00:58
History2015-08-05 GDR Created.