Richard L. Hamilton wrote:
>> Doug Scott wrote:
>>     
>>>> I've installed build 64a Solaris Express, and
>>>>         
>> desktop
>>     
>>>> operations on JDS are still very sluggish. It's
>>>> slower than running Ubuntu 7.04 from CD ... Part
>>>>         
>> of
>>     
>>>> this seems to stem from UFS - with zfs I have
>>>> experienced a considerable improvement in this
>>>> regard. It's still not what one expects, but it's
>>>> much better.
>>>>
>>>> I have no figures at all to prove this. This is
>>>>         
>> all
>>     
>>>> just a feeling of how the systems performs. Java
>>>> Workstation, single 2,4 GB Opteron, 2 GB RAM, 500
>>>>         
>> GB
>>     
>>>> hard disk (zfs boot/ufs boot) etc.
>>>>     
>>>>         
>>> One thing I just noticed is that kmem_flags in the
>>>       
>> kernel on my machine was set to enable kernel memory
>> debugging. Over 200 MB (and growing) was held in the
>> kmem_bufctl_audit_cache. Performance became sluggish
>> the more I used the machine.
>>     
>>> Adding "set kmem_flags=0" to /etc/system and
>>>       
>> rebooting fixed the problem.
>>     
>>> After the reboot check kmem_flags with mdb. It now
>>>       
>> should be zero.
>>     
>>> root at prae> echo "kmem_flags/D" | mdb -k
>>> kmem_flags:
>>> kmem_flags:     0
>>>
>>> Doug
>>>       
>> I probably should add that this is enabled if you are
>> running a debug 
>> kernel.
>>
>> Doug
>>
>> From: usr/src/uts/common/os/kmem.c
>>
>> #ifdef DEBUG
>> int kmem_flags = KMF_AUDIT | KMF_DEADBEEF |
>> KMF_REDZONE | KMF_CONTENTS;
>> #else
>> int kmem_flags = 0;
>> #endif
>>     
>
> Which of those flags implies the growing memory consumption?
> Would there be any value (in terms of debugging) in leaving
> the others on, rather than setting kmem_flags to 0?
>   
Better than me explaining it :) 
http://docs.sun.com/app/docs/doc/816-5041/kmem-1?a=view

For a normal desktop user there is probably no need to set kmem_flags to 
anything other then 0 unless you suspect a problem. If you run a 
non-debug kernel then 0 should be the default.

Doug

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