Solaris 10 - Increasing Number of Processes Per User

Solaris 10 - Increasing Number of Processes Per User We came across this problem when working with one of the ISV application. We were simulating workload for performance tests and realized that the load simulation tool was generating 30000+ processes/LWP. The load siluation tools was running on UltraSPARC T2 based system with Solaris 10 and 32 GB RAM. Looked up the resources on the web for increasing the number of processes on Solaris 10 system on PER UID. Came across couple of blog entries (Giri Mandalika, Spiralbound.net) which provided good starting point but were not complete solution to our problem. We needed to increase the number of processesper user to more than current setting of 30000 bash-3.00# ulimit -a core file size (blocks, -c) unlimited data seg size (kbytes, -d) unlimited file size (blocks, -f) unlimited open files (-n) 260000 pipe size (512 bytes, -p) 10 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 29995 virtual memory (kbytes, -v) unlimited Trying to increase the "max user processes" would fail with the following error: bash-3.00# ulimit -u 50000 bash: ulimit: max user processes: cannot modify limit: Invalid argument bash-3.00# After going through the Solaris 10 Tunable Guide for Process sizing learned that there are 5 related parameters related to process sizing. maxusers - The maximum number of processes on the system, The number of quota structures held in the system. The size of the directory name look-up cache (DNLC) reserved_procs - Specifies the number of system process slots to be reserved in the process table for processes with a UID of root pidmax - Specifies the value of the largest possible process ID. Specifies the value of the largest possible process ID. Valid for Solaris 8 and later releases. max_nprocs - Specifies the maximum number of processes that can be created on a system. Includes system processes and user processes. Any value specified in /etc/system is used in the computation of maxuprc. maxuprc - Specifies the maximum number of processes that can be created on a system by any one user Looked at the current values for these parameter: bash-3.00# echo reserved_procs/D | mdb -k reserved_procs: reserved_procs: 5 bash-3.00# echo pidmax/D | mdb -k pidmax: pidmax: 30000 bash-3.00# echo maxusers/D | mdb -k maxusers: maxusers: 2048 bash-3.00# bash-3.00# echo max_nprocs/D | mdb -k max_nprocs: max_nprocs: 30000 bash-3.00# bash-3.00# echo maxuprc/D | mdb -k maxuprc: maxuprc: 29995 So, in order to set the max per user processes in this scenario, we were required to make the changes to "pidmax" (upper cap), maxusers, max_nprocs & maxuprc Sample entries in /etc/system & reboot set pidmax=60000 set maxusers = 4096 set maxuprc = 50000 set max_nprocs = 50000 After making the above entries, we were able to increase the max user processes to 50000. bash-3.00# ulimit -a core file size (blocks, -c) unlimited data seg size (kbytes, -d) unlimited file size (blocks, -f) unlimited open files (-n) 260000 pipe size (512 bytes, -p) 10 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 49995 virtual memory (kbytes, -v) unlimited bash-3.00# bash-3.00# echo reserved_procs/D | mdb -k reserved_procs: reserved_procs: 5 bash-3.00# echo pidmax/D | mdb -k pidmax: pidmax: 60000 bash-3.00# echo max_nprocs/D | mdb -k max_nprocs: max_nprocs: 50000 bash-3.00# echo maxuprc/D | mdb -k maxuprc: maxuprc: 50000 bash-3.00# Note: If you are operating within the 30000 limit (default pidmax setting) the blog entry referred above seems to work fine. If you are looking at increasing the processes beyond 30000, it we need to make adjustment to other dependent parameters stated in this blog entry.