On Sat, Jun 26, 2021 at 01:17:33PM +0200, Alexander Bluhm wrote: > Hi, > > I would like to show the time spent in userland also when analyzing > kernel stack in flame graph. Here are examples when building a bsd > kernel on a 4 core machine. > > kernel only > http://bluhm.genua.de/perform/results/2021-06-21T09%3A44%3A18Z/2021-06-21T00%3A00%3A00Z/btrace/time_-lp_make_-CGENERIC.MP_-j4_-s-btrace-kstack.1.svg > > kernel + userland > http://bluhm.genua.de/perform/results/2021-06-21T09%3A44%3A18Z/2021-06-21T00%3A00%3A00Z/btrace/time_-lp_make_-CGENERIC.MP_-j4_-s-btrace-kstack.2.svg > > To evaluate the performance of the system you have to compare time > spent in kernel with activity in userland. Only when you see both, > you get the whole picture. Goal is to optimize the kernel to spend > more time in userland tasks. > > No information is lost. Wenn you click on the kernel field in the > kernel + userland graph, you get that same information as in kernel > only. > > In the old graph you see one @[ field. This is a parsing bug as > @[]: 87353 is not a valid line for flame graph generation. This > is the time spent in userland and my diff makes it explicit.
OK kn
