Hello,
One of my Russian customer is doing a Progress DB test using readprobe tool. To do so, he's using remotely in France an IBM P570 power6 with AIX 5.3 (TL6 SP3). the results we have are quite disturbing.
With a partition configured with 4 dedicated cpus (SMT is off), we're reaching the maximum rec/s (411000) with 4 _progress processes. OK. That's normal if I believe the graphs I've seen on Tom Bascom site (the max perf occurs with number of _progres processes = number of cpus).
When we add two more cpus (so we have now 6 cpus) and do the same test, the maximum is now with 6 processes (still normal), but we're reaching a little bit less than 410000 rec/s. so with 6 cpus and 6 processes, we're doing less perf than with 4 cpus and 4 processes. Strange !
Much stranger : With a 6 cpu lpar, when running 4 processes, I thought we should have had the same perf than on a 4 cpu lpar with 4 processes as in both case we're really consumming 4 cpus (In the second case, we have 2 cpus doing nothing). But no : 6 cpus available and 4 processes, we're reaching only 309000 rec/s, so 25% less than with 4 cpus available and 4 processes.
Any ideas ?
One of my Russian customer is doing a Progress DB test using readprobe tool. To do so, he's using remotely in France an IBM P570 power6 with AIX 5.3 (TL6 SP3). the results we have are quite disturbing.
With a partition configured with 4 dedicated cpus (SMT is off), we're reaching the maximum rec/s (411000) with 4 _progress processes. OK. That's normal if I believe the graphs I've seen on Tom Bascom site (the max perf occurs with number of _progres processes = number of cpus).
When we add two more cpus (so we have now 6 cpus) and do the same test, the maximum is now with 6 processes (still normal), but we're reaching a little bit less than 410000 rec/s. so with 6 cpus and 6 processes, we're doing less perf than with 4 cpus and 4 processes. Strange !
Much stranger : With a 6 cpu lpar, when running 4 processes, I thought we should have had the same perf than on a 4 cpu lpar with 4 processes as in both case we're really consumming 4 cpus (In the second case, we have 2 cpus doing nothing). But no : 6 cpus available and 4 processes, we're reaching only 309000 rec/s, so 25% less than with 4 cpus available and 4 processes.
Any ideas ?