collecting pv entries -- suggest increasing PMAP_SHPGPERPROC

FreeBSD freebsd at
Mon Oct 27 12:41:03 PDT 2008

Simon Chang a écrit :
>> collecting pv entries -- suggest increasing PMAP_SHPGPERPROC
>> I've read that this is mainly caused by Apache spawning too many processes.
>> Everyone seems to suggest to decrease the MaxClients directive in Apache(set
>> to 450 at the moment), but here's the problem...i need to increase it !
>> During peaks all the processes are in use, we even have little drops
>> sometime because there isn't enough processes to serve the requests. Our
>> traffic is increasing slowly over time so i'm affraid that it'll become a
>> real problem soon. Any tips on how I could deal with this situation,
>> Apache's or FreBSD's side ?
> On page 85 of Michael Lucas' "Absolute BSD", there is a solution to
> your problem that someone else had come across before.  The solution
> involves (1) increasing the PMAP_SHPGPERPROC parameter in the kernel
> to a higher value and rebuilding the kernel, and (2) increasing the
> amount of physical RAM to complement it.
> For more details, go to
> Good luck,
> Simon Chang

Thanks for the links, pretty helpful but this server is the only 
production web server we have. I don't really like the idea of 
recompiling the kernel with a new option...

I don't really understand why we are getting this error since there is 
plenty of Inactive RAM in the system (2G inactive on a 4G server with 
amd64). Is this a "normal" error in this case?

Thank you for your quick reply.

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