Optimizing existing large codebase Measure Mem threads Defining our performance Key question is:what is performance o simply going faster not at all costs(money,physics results) o making better use of the hardware most of the time hardware is cheaper than people o you need to define your "Key Performance Indicators" e.g.nb Evts/s/S with constant man power for a trigger o and get a clear idea of your different costs flops/S of your machines including network,cabling,cooling,buildings,... ◆human costs ●cost of transition perf tools bottlenecks 7/57 S.Ponce-CERNOptimizing existing large codebase 7 / 57 S. Ponce - CERN Measure Modernize Mem threads low level c/c perf tools bottlenecks Defining our performance Key question is : what is performance simply going faster ? not at all costs (money, physics results) making better use of the hardware most of the time hardware is cheaper than people ! you need to define your “Key Performance Indicators” e.g. nb Evts / s / ✩ with constant man power for a trigger and get a clear idea of your different costs flops/✩ of your machines including network, cabling, cooling, buildings, ... human costs cost of transition