Solaris 10 : Too many Virtual CPU's : Physical CPU load never exceeds 3.2%

Question

I'm on a Solaris 10 machines with the following characteristics.

uname -a

SunOS ********* 5.10 Generic_137111-07 sun4v sparc SUNW,SPARC-Enterprise-T5220

psrinfo -pv

The physical processor has 32 virtual processors (0-31)

UltraSPARC-T2 (cpuid 0 clock 1165 MHz)

When I run different tasks the "top" command show me that each process takes max 3.2% of total CPU. I guess this is normal as a process only takes one virtual CPU.

The work we do involves sequential tasks, little parallel work. This means that we usually see perhaps two processes (other than system) running, taking up ~6% of CPU and ~93% idle.

Is there anyway of redefining the number of CPU's, or some other kind of munging which would allocate a greater share of CPU processing power per process ?

As the post show, I'm not a Solaris sysadmin, and would appreciate any links to resources that could advance my understanding of Virtual CPU usage/management .

Best regards,

Colm

Answer 1

There is nothing doable from the OS side with a T5220 (UltraSPARC T2 based). The only way is to work at the userland side and better parallelize your workload.

Starting with the UltraSPARC T4 series, the critical thread feature allows to automatically assign a whole chip to a single thread and then boost performance in your use case.