Krassimir Slavchev wrote:
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
