performance degradation in 6.2 when adding a second quad core chip

Noisex noisex at
Fri Feb 22 16:55:01 UTC 2008

So Benjamin you want to tell, that adding additional CPU decrease the
performance on 6.2? How did you made tests? 
	I just want to know because in my plans to the next week is also add
2nd CPU (dual core) and some additional RAM to one of the my HP Proliant
DL360 (generaly mysql db server) because due to heavy MySQL usage nearly to
100% or even more sometimes some of my customers are not very happy with
service like that (long load time).

Server: HP proliant G4P DL360, CPU 1x3Ghz dual core, RAM: 4Gb (on system i
can see 3Gb :) ), SCSI 146Gbx2 (RAID 1+0 with smartarray controller p4600).
OS: FreeBSD 6.2, SMP

Current load of mysql process:

70348 mysql           17  20    0   450M   234M kserel 1 111.4H 99.46%

MySQL Version 5.0.51 i386
Uptime = 28 days 18 hrs 51 min 19 sec
Avg. qps = 567
Total Questions = 469973918
Threads Connected = 4

however that may be:
1) on next week i will upgrade to 6.3 but i dont know will it give some
performance or not but generaly i wait final relase of 7.0 with ULE
2) i will add +4GB RAM
3) i will add 2nd CPU

If it will not help, i will consider about mysql clustering...btw, is it
ok/done on freebsd?

p.s what you guys could recommend about enabled/disabled hyperthreading on
intel? Will it increase performance or over the left decrease?

-Gatis Rumbens

-----Original Message-----
From: owner-freebsd-performance at
[mailto:owner-freebsd-performance at] On Behalf Of benjamin
Sent: Friday, February 22, 2008 4:36 PM
To: freebsd-performance at
Subject: Re: performance degradation in 6.2 when adding a second quad core

On Feb 21, 2008, at 17.49, Kris Kennaway wrote:

> benjamin thielsen wrote:
>> hi folks-
>> we've been experiencing some interesting behavior on single quad  
>> core computers as compared to dual quad core computers.
> Yes, this can happen when you run into concurrency bottlenecks in  
> the application or in the kernel.
>> it appears that adding a second processor to the system (leaving it  
>> otherwise untouched) actually decreases performance.  we've got a  
>> small rudimentary test process, built in house, that does  
>> postgresql queries (selects) via http requests (apache2/php5).
> 7.0 will perform much better than 6.x on SMP workloads in general,  
> however TCP I/O is not yet at the point where it can make efficient  
> use of many processors (there has been a lot of work on TCP in 7.0,  
> but it is not yet at the stage where a performance payoff will be  
> seen with more than about 4 CPUs).  This is one of the projects that  
> we will be working on this year, so you can expect future releases  
> to have improved concurrent TCP performance.
> There may be other issues, so if you like you can enable  
> LOCK_PROFILING and obtain a trace when your workload is running (see  
> the manpage).  You should also try the ULE scheduler on 7.0.

i apologize - i neglected to mention that we are using ule on 7.0.

what do you guys generally endorse/recommend for local(non-network)  
load/performance testing?

freebsd-performance at mailing list
To unsubscribe, send any mail to
"freebsd-performance-unsubscribe at"

More information about the freebsd-performance mailing list