Re: [1/1][PATCH] nproc v2: netlink access to /proc information

William Lee Irwin III
2004-09-15T20:23:56Z

On Wed, Sep 15, 2004 at 10:02:30PM +0200, Roger Luethi wrote:
> Here's another thing we haven't been able to do with /proc: Finding out
> the relative cost of computing the elements we offer to user space.
> I ran a test program against 2.6.9-rc2-bk1 + nproc to get:
> Testing all process fields, best out of 10
> FieldID CPU (s) Wall (s) Label
> 0x03000002 0.140000 0.202728 NOP
> 0x21000100 0.150000 0.210021 Name
> 0x22000105 0.120000 0.204886 PID
> 0x22000109 0.130000 0.205319 UID
> 0x22000117 0.140000 0.215275 VmSize
> 0x22000118 0.130000 0.214240 VmLock
> 0x22000119 0.120000 0.214870 VmRSS
> 0x22000120 0.160000 1.020574 VmData
> 0x22000121 0.140000 1.021185 VmStack
> 0x22000122 0.170000 1.021619 VmExe
> 0x22000123 0.170000 1.020045 VmLib
> 0x23000421 0.140000 0.220748 wchan
> Ignore the absolute values (I requested each field individually for all
> processes on my workstation, 1000 times). The cost of walking all vmas
> for VmData & Co. is very visible.

Try this again after applying my updates, which make it equivalent to the
algorithms used internally by fs/proc/task_mmu.c.

-- wli