On 05/08/2018 09:44 AM, Ben Greear wrote: > Hello, > > I am trying to track down a performance regression that appears to be between > 4.13 > and 4.14. > > I first saw the problem with a hacked version of pktgen on some ixgbe NICs. > 4.13 can do > right at 10G bi-directional on two ports, and 4.14 and later can do only > about 6Gbps. > > I also tried with user-space UDP traffic on a stock kernel, and I can get > about 3.2Gbps combined tx+rx > on 4.14 and about 4.4Gbps on 4.13. > > Attempting to bisect seems to be triggering a weirdness in git, and also lots > of commits > crash or do not bring up networking, which makes the bisect difficult. > > Looking at perf top, it would appear that some lock is probably to blame.
perf record -a -g -e cycles:pp sleep 5 perf report Then you'll be able to tell us which lock (or call graph) is killing your perf.
