Davidlohr Bueso <dave@xxxxxxxxxxxx> writes: > I ran this on a 40-core (no ht) Westmere with two benchmarks. The first > is Manfred's sysvsem lockunlock[1] program which uses _processes_ to, > well, lock and unlock the semaphore. The options are a little > unconventional, to keep the "critical region small" and the lock+unlock > frequency high I added busy_in=busy_out=10. Similarly, to get the > worst case scenario and have everyone update the same semaphore, a single > one is used. Here are the results (pretty low stddev from run to run) > for doing 100,000 lock+unlock. > > - 1 proc: > * vanilla > total execution time: 0.110638 seconds for 100000 loops > * dirty > total execution time: 0.120144 seconds for 100000 loops > > - 2 proc: > * vanilla > total execution time: 0.379756 seconds for 100000 loops > * dirty > total execution time: 0.477778 seconds for 100000 loops > > - 4 proc: > * vanilla > total execution time: 6.749710 seconds for 100000 loops > * dirty > total execution time: 4.651872 seconds for 100000 loops > > - 8 proc: > * vanilla > total execution time: 5.558404 seconds for 100000 loops > * dirty > total execution time: 7.143329 seconds for 100000 loops > > - 16 proc: > * vanilla > total execution time: 9.016398 seconds for 100000 loops > * dirty > total execution time: 9.412055 seconds for 100000 loops > > - 32 proc: > * vanilla > total execution time: 9.694451 seconds for 100000 loops > * dirty > total execution time: 9.990451 seconds for 100000 loops > > - 64 proc: > * vanilla > total execution time: 9.844984 seconds for 100032 loops > * dirty > total execution time: 10.016464 seconds for 100032 loops > > Lower task counts show pretty massive performance hits of ~9%, ~25% > and ~30% for single, two and four/eight processes. As more are added > I guess the overhead tends to disappear as for one you have a lot > more locking contention going on. Can you check your notes on the 4 process case? As I read the 4 process case above it is ~30% improvement. Either that is a typo or there is the potential for quite a bit of noise in the test case. Eric _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers