On Mon, Jan 30, 2023 at 1:35 PM Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > On Mon, Jan 30, 2023 at 9:47 AM Paul Moore <paul@xxxxxxxxxxxxxx> wrote: > > > > I should add, do you have any particular test script you use? If not, > > that's fine, I just cobble something together, but I figured if you > > had something already it would save me having to remember the details > > on the perf tools. > > So I've done various things over the years, including just writing > special tools that do nothing but a recursive 'stat()' over and over > again over a big tree, just to pinpoint the path lookup costs (big > enough of a tree that you see actual cache effects). Then do that > either single-threaded or multi-threaded to see the locking issues. > > But what I keep coming back to is to just have a fully built "make > allmodconfig" tree - which I have _anyway_, and then doing > > perf record -e cycles:pp make -j64 > ... > Put another way: there's nothing _special_ about the above, except for > the "it's a real load that does actually show a few core kernel > areas". Thanks. -- paul-moore.com
