Andres Freund <and...@anarazel.de> Sunday 17 April 2011 20:02:11 > On Sunday 17 April 2011 19:26:31 Radosław Smogura wrote: > > Kernel merges vm_structs. So mappings are compacted. I'm not kernel > > specialist, but skipping memory consumption, for not compacted mappings, > > kernel uses btrees for dealing with TLB, so it should not matter if > > there is 100 vm_structs or 100000 vm_structs. > > But the CPUs TLB cache has maybe 16/256 (1lvl, 2nd) to 64/512 entries. That > will mean that there will be cachemisses all over. > Additionally your scheme requires flushing it regularly... > > Andres
I only know Phenom has 4096 entries I think and this covers 16MB of memory. But I was taking about memory usage of struct vm_struct in kernel. I tries as well with huge pages, but I can't write really fast allocator for this, it's slower then malloc, maybe from different reasons. Regards, Radek -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
