[dpdk-dev] Performance impact of "declaring" more CPU cores

2019-10-24 Thread Tom Barbette
Hi all, We're experiencing a very strange problem. The code of our application is modified to always use 8 cores. However, when running with "-l 0-MAXCPU", with MAXCPU varying between 7 and 15 (therefore "allocating" more *unused* cores), the performance of the application change. It can be m

Re: [dpdk-dev] Performance impact of "declaring" more CPU cores

2019-10-25 Thread David Christensen
The only useful observation we made is that when we are in a "bad case", the LLC has more cache misses. Have you looked closely at the CPU topology on your platform, can you provide some examples here of what you're seeing? The hwloc package is very useful in visualizing how your logical core

Re: [dpdk-dev] Performance impact of "declaring" more CPU cores

2019-10-30 Thread Tom Barbette
bette; dev@dpdk.org Objet : Re: [dpdk-dev] Performance impact of "declaring" more CPU cores > The only useful observation we made is that when we are in a "bad case", > the LLC has more cache misses. Have you looked closely at the CPU topology on your platform, can you pro