[LLVMdev] Inline hint for methods defined in-class

David Chisnall David.Chisnall at cl.cam.ac.uk
Thu Jul 9 01:09:30 PDT 2015


On 9 Jul 2015, at 08:00, Xinliang David Li <xinliangli at gmail.com> wrote:
> 
> You need to be more specific on why the regression is problematic (and more so than missed opportunities).  Text size increase (shared and much smaller than heap) is usually not a big issue except for tiny devices which is likely to use Os/Oz in the build. For servers, there are are simple rules to compare cpu vs ram resource cost.

Text size increase also means more TLB and i-cache misses.  We’ve observed that single-program benchmarks show this quite poorly, but the aggregate increase in i-cache and TLB pressure across the entire system can degrade performance overall on a typical desktop workload (not so relevant for single-application servers, but very relevant for server VMs).

I believe some folks at Apple did a more systematic analysis of this, but I don’t know if their detailed results are public.

David






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