SAS performance on Sun Fire[TM] X4450 servers and Sun Blade[TM] X6450 blade servers running Solaris[TM] 10 could be slower than expected

Asset ID:	1-71-1019712.1
Update Date:	2009-12-21
Keywords:

Solution Type Technical Instruction Sure

Solution 1019712.1 : SAS performance on Sun Fire[TM] X4450 servers and Sun Blade[TM] X6450 blade servers running Solaris[TM] 10 could be slower than expected

Related Items


Sun Blade X6450 Server Module
 Sun Fire X4450 Server
 Solaris SPARC Operating System

Related Categories


GCS>Sun Microsystems>Servers>Blade Servers
 GCS>Sun Microsystems>Operating Systems>Solaris Operating System
 GCS>Sun Microsystems>Servers>x64 Servers

PreviouslyPublishedAs
244386

Description
Sun Fire X4450 Systems and Sun Blade X6450 Systems, which have Intel(R) Xeon(R) MP 7400 series processors may experience SAS performance issues if running Solaris[TM] 10

Performance for CPU/memory intensive applications could be slower than expected due to BugID 6726459.

Steps to Follow
SAS users running applications on Solaris 10/x64 on systems utilizing the Intel(R) Xeon(R) Processor MP 7400 series may experience a reduction in performance of CPU intensive applications.

Systems with Intel(R) Xeon(R) Processor MP 7400 series (psrinfo -pv reports family 6 model 29 all step) running Solaris 10 10/08 might experience reduced performance and increased power consumption. This might occur due to an issue where CPUs do not quiesce, preventing power management while idle. No error message is displayed.
The issue is described in Bug ID 6726459:
Bug ID 6726459 : i86_mwait Function does not function as designed
and is currently scheduled to be addressed in Solaris 10 Update 7.
A workaround is described in the Solaris 10/08 (Update 6) release notes but can be used for all Solaris 10 releases up to and including Update 6
Workaround:
Add the following line to the /etc/system file and then reboot:
set idle_cpu_prefer_mwait=0
Refer to the Solaris 10, Update 6 release documentation for more information: http://docs.sun.com/app/docs/doc/820-5245
Here are a list of DO and DO NOT items to check:
DO
- Check for Intel® Xeon® Processor MP 7400 series with psrinfo(1M) to see if it is similar to this example:
bash-3.00# psrinfo -pv
The physical processor has 6 virtual processors (0 4-8)
x86 (chipid 0x0 Genuine Intel family 6 model 29 step 1 clock 2400 MHz)
Intel(r) CPU @ 2.40GHz
- Check for the Solaris 10 release (Example below shows Update 5)
bash-3.00# cat /etc/release
Solaris 10 5/08 s10x_u5wos_10 X86
Copyright 2008 Sun Microsystems, Inc. All Rights Reserved.
Use is subject to license terms.
Assembled 24 March 2008
- If running Solaris 10 Update 6 or less, OR any Solaris 10 release where Bug 6726459 is specifically not mentioned in the Bugs fixed section of the release notes, add the above workaround to /etc/system and reboot.
If there are further questions, contact SAS or Sun technical support
DO NOT
- Add the mwait /etc/system above change if running any any processors other than the Intel(R) Xeon(R) Processor MP 7400 series. This includes any UltraSPARC, SPARC, AMD Opteron or other Intel processors (i.e.: Intel dual or quad core processors).
If running non Intel(R) Xeon(R) Processor MP 7400 series and the mwait setting above is enabled in /etc/system, disable the change and reboot.
-Persist the change if bug 6726459 is addressed as per the Solaris release notes for the update release that is currently installed. Remove the /etc/system change above and reboot. The kernel fix is currently scheduled for Solaris 10, Update 7 at which time the workaround should be removed.

Product
Sun Fire X4450 Server
Sun Blade X6450 Server Module
Solaris 10 Operating System for x86 Platforms

Internal Comments
Sample performance data without workaround - Sun / SAS Internal information

Here is a sample of performance differentials without the workaround. Customer can be told if they ask but the information should not be emailed or published.

FYI- i recently did some sas testing on the new intel dunnington (six core) processors. while the previous quad core (tigerton) processors in my 4450/tucani clocked in a bit higher (and thus should have better raw performance), dunnington performance was surprisingly poor - up to 6-8X times slower. This was due to an existing bug

sample test times *before* the workaround:

cumulative test time - 46 tests summed
tigerton: 4 hrs, 4 min
dunnington: 9 hrs, 26 min

most tests were 2-3X slower, some worse. one test, a general linear model (one of the threaded tests but both tests clamped to 4 threads), went fairly psychotic on dunnington:

beverage2
tigerton: 10 min
dunnington: 1 hr, 2 min

With the workaround, performance was in line as expected (accounting for the difference in clock rate between tigerton and dunnington)

Intel six core SAS performance Dunnington Sun Fire X4450 Server

Change History
Tech reviewer was not in TSC. Email of approval by tech reviewer -
Subject:

Re: [Fwd: peer review request for sunsolve doc]

From:

Cherry Shu <[email protected]>

Date:

Thu, 30 Oct 2008 11:56:42 -0400

To:

Maureen Chew <[email protected]>

To:

Maureen Chew <[email protected]>

CC:

[email protected]

Hi Maureen,

I did read your article as I also have a project on X4450 (but not w/
Dunnington processor). It's a good tech note and I give it a thumb up.

Regards,

Cherry

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