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Date:      Thu, 20 Dec 2007 14:24:01 +0200
From:      Krassimir Slavchev <krassi@bulinfo.net>
To:        FreeBSD <freebsd-stable@freebsd.org>
Subject:   Performance!
Message-ID:  <476A5EE1.9000003@bulinfo.net>

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Hello,

I have read all related threads about performance problems with multi
core systems but still have no idea what to do to make thinks better.
Below are results of testing postgresql on HP DL380G5 using sysbench.
The results are comparable to:
http://blog.insidesystems.net/articles/2007/04/11/postgresql-scaling-on-6-2-and-7-0
but the same tests running on the same hardware using Linux (kernel
2.6.18-53.1.4.el5 SMP x86_64) are very different.
PostgreSQL is tuned equal.

dmesg:
...
CPU: Intel(R) Xeon(R) CPU           X5450  @ 3.00GHz (3000.02-MHz
K8-class CPU)
  Origin = "GenuineIntel"  Id = 0x10676  Stepping = 6

Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>

Features2=0xce3bd<SSE3,RSVD2,MON,DS_CPL,VMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,DCA,<b19>>
  AMD Features=0x20000800<SYSCALL,LM>
  AMD Features2=0x1<LAHF>
  Cores per package: 4
usable memory = 8575655936 (8178 MB)
avail memory  = 8288337920 (7904 MB)
ACPI APIC Table: <HP     ProLiant>
FreeBSD/SMP: Multiprocessor System Detected: 8 CPUs
...

test:
sysbench --num-threads=${i} --test=oltp --pgsql-user=bench
- --pgsql-db=bench --db-driver=pgsql --max-time=60 --max-requests=0
- --oltp-read-only=on run

tuning:
kern.ipc.shmmax=2147483647
kern.ipc.shmall=524288
kern.ipc.semmsl=512
kern.ipc.semmap=256
kern.ipc.somaxconn=2048
kern.maxfiles=65536
vfs.read_max=32

kern.ipc.semmni=256
kern.ipc.semmns=2048

results:
FreeBSD 7.0-BETA4 amd64 (cvsup on 20.12) GENERIC with SCHED_ULE
#threads        #transactions/sec       user/system
1               500                     7.4%,5.3%
5               1990                    30.9%,23.4%
10              2510                    39.9%,35.0%
20              2549                    44.5%,43.5%
40              1921                    29.8%,59.4%
60              1580                    22.7%,70.6%
80              1341                    18.9%,75.9%
100             1227                    16.5%,79.3%

Linux
#threads        #transactions/sec
1               693
5               3539
10              5789
20              5791
40              5661
60              5517
80              5401
100             5319


What can be done to improve these results?

Best Regards

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