There was a performance test a few years ago that showed running with timer pops ON gives better transaction rates under SAP, and probably other high transaction rate workloads. The rule of thumb was that if the server is usually under heavy CPU utilization processing lots of transactions per second, leave the timer pop ON ( 1 ) .
But - this was like two years ago when the timer patch first came out. It may have changed since then. For a production server test it both ways and see if it makes a difference. For Test and Development machines, leave it OFF ( 0 ). Jay Brenneman Linux Test and Integration Center T/L: 295 - 7745 Extern: 845 - 435 - 7745 [EMAIL PROTECTED] "Wiggins, Mark" <[EMAIL PROTECTED]> Sent by: Linux on 390 Port <[email protected]> 24/03/2005 10:41 Please respond to Linux on 390 Port To [email protected] cc Subject Re: More CPU in SLES9 So I'm sure this has been asked before but I couldn't find much about it. If the "default" is set to 1, is there a down side to setting it to 0? In other words, in what types of circumstances would you NOT want to change this variable? Mark Wiggins University of Connecticut Operating Systems Programmer 860-486-2792 -----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of John Schnitzler Jr Sent: Wednesday, March 23, 2005 5:07 PM To: [email protected] Subject: Re: More CPU in SLES9 Sorry, You're right, I just googled it and the value should be 0. The Novell/SUSE SLES 8 and SLES 9 distribution delivers the kernel with the Timer Patch enabled. It can be disabled by the kernel config option CONFIG_NO_IDLE_HZ=n and a kernel recompile. Alternatively the Timer Patch can be activated and deactivated with the following convenient method. Use the sysctl command to switch the setting in the proc file system: 1. 'sysctl -w kernel.hz_timer=1' enables the 100 Hz timer. The Timer Patch is deactivated. 2. 'sysctl -w kernel.hz_timer=0' disables the 100 Hz timer. The Timer Patch is activated. Regards, John ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
