I have seen the discussions about fastlock patch and lazy-vxid  performance 
degradation, so I decided to test it myself.

The setup:
- hardware
Supermicro blade 
6xSAS @15k on LSI RAID:
 1 disk for system + pg_xlog 
 4 disk RAID 10 for data 
 1 disk for spare 
2 x Xeon E5405 @2GHz (no HT), 8 cores total

- software 
Debian Sid, linux-
Postgresql 9.1 beta2, compiled by debian sources
incrementally applied fastlock v3 and lazy-vxid v1 patches. I have to resolve 
manually a conflict in src/backend/storage/lmgr/proc.c
Configuration: increased shared_mem to 2G, max_connections to 500

- pgbench
initiated datasert with scaling factor 100
example command invocation: ./pgbench -h -n -S -T 30 -c 8 -j 8 -M 
prepared pgtest


clients beta2   +fastlock       +lazyvzid     local socket  
8       76064       92430           92198           106734
16      64254       90788           90698           105097
32      56629       88189           88269           101202
64      51124       84354           84639            96362
128     45455       79361           79724            90625
256     40370       71904           72737            82434

All runs are executed on warm cache, I made some runs for 300s with the same 
results (tps).
I have done some runs with -M simple with identical distribution across cleints.

I post this results because they somehow contradict with previous results 
posted on the list. In
my case the patches does not only improve peak performance but also improve the 
under load - without patches the performance with 256 clients is 53% of the 
peak performance 
that is obtained with 8 clients, with patches the performance with 256 client 
is 79% of the peak 
with 8 clients. 

Best regards
Luben Karavelov

P.S. Excuse me for starting new thread - I am new on the list.

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