Thomas Maier-Komor schrieb:
Hi,
I am once again looking at a kstat output and trying to understand what
> some of these fields might mean and what their unit might be.
> Unfortunately the units aren't documented anywhere, are they?
Use the source, Luke!
biostats is probably the statistics for the ddi I/O buffers of Solaris
> that are accessible via bioinit(9f). So lookup and cache hits and misses
> are counted here. Unit is probably "each".
http://cvs.opensolaris.org/source/xref/on/usr/src/uts/common/os/bio.c#biostats
Later in the same file you can look up when the statistics will be
incremented. But I don't think biostats are of much interest any more.
Concerning ufs_inode_cache and hsfs_hsnode_cache, I'd like to know what
> unit buf_inuse has. Is it kB or pages or something else?
Unit is number of elements, as with all kstat entries of class "kmem_cache".
BTW: is the result sysconf(_SC_CPUID_MAX) the maximum id a processor can
have or the maximum id no processor will ever have?
Well, sysconf(_SC_CPUID_MAX) ends finally in the kernel:
http://cvs.opensolaris.org/source/xref/on/usr/src/uts/common/syscall/sysconfig.c#165
max_cpuid is initialized to a default value of (NCPU - 1) - some
architectures may re-set max_cpuid:
http://cvs.opensolaris.org/source/xref/on/usr/src/uts/common/os/cpu.c#max_cpuid
So _SC_CPUID_MAX returns the maximum possible value. If a architecture
supports cpuids from 0..31 (total 32 cpus) then sysconf(_SC_CPUID_MAX) will
return 31. So you should iterate over
for(cpuid = 0; cpuid <= cpuid_max; ++cpuid)
...
But for my performance gathering tool I wrote a few years ago I didn't
bother to get _SC_CPUID_MAX at all. I just iterated over all kstat entries
while searching for the right kstat modules:
ncpu = 0;
for(ksp = kc->kc_chain; ksp != NULL; ksp = ksp->ks_next)
{
cpu_stat_t *cp;
if((ksp->ks_type != KSTAT_TYPE_RAW) ||
(strncmp(ksp->ks_module, "cpu_stat", 8)))
continue;
if(kstat_read(kc, ksp, NULL) == -1)
continue;
++ncpu;
[...]
}
It really isn't that inefficient. Even on large machines with many RAM, lots
of disks and CPUs the cumulative running time was ~60 minutes over a period
of >200 days. The program fetched every 60 seconds performance counters from
disks, network, memory and cpu. Only on Solaris 2.6 accessing the kstat
system_misc module blocked for a few seconds on machines with large memory.
Daniel
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