Re: load average with multi-core CPU's
On 22/09/2011 22:59, Rodrigo Gonzalez wrote: It is the number of task waiting in queue to be runbut IO is important...if 2 processes are waiting for IO and it is completely saturated they will be kept in queue so load will get higher No, this is how Linux does the calculation. For FreeBSD, if a process is waiting or IO, it is sleeping and thus not runnable. Linux has the iowait (w) state in addition to usr/sys/idle states and counts processes waiting for IO as runnable - which never made sense to me as it is counting apples as oranges. (yes, IO saturation is important for server status but it needs to be inspected separately - the LA number is too coarse for this). signature.asc Description: OpenPGP digital signature
Re: load average with multi-core CPU's
On 9/22/11 10:59 PM, Rodrigo Gonzalez wrote: On 09/22/2011 04:29 PM, Mark Felder wrote: On Thu, 22 Sep 2011 10:22:43 -0500, Henry M henr...@gmail.com wrote: Hi all, Can someone explain, or point me to correct documentation on what the load average on top/uptime is actually displaying? Load average is average number of processes in the run queue for the 1, 5, and 15 minute intervals. If you have a quad core CPU a 4.00 load average means you've been keeping the CPU busy at 100%. Not exactly as I understand itIO (disk, network or whatever) affects it too... It is the number of task waiting in queue to be runbut IO is important...if 2 processes are waiting for IO and it is completely saturated they will be kept in queue so load will get higher I think there are other things that affect load average but are over my current knowledge... Regards Rodrigo Gonzalez Actually, I could be wrong but that is the number of tasks both in the waiting *AND* the running queue. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: load average with multi-core CPU's
On 9/22/11 10:34 PM, Henry M wrote: Thanks- That's what I thought it was. I'm trying to settle an argument at work : ) http://xkcd.com/386/ Enjoy ;) ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: load average with multi-core CPU's
From owner-freebsd-questi...@freebsd.org Fri Sep 23 03:15:37 2011 Date: Fri, 23 Sep 2011 10:12:51 +0200 From: Damien Fleuriot m...@my.gd.r-bonomi.com To: freebsd-questions@freebsd.org Subject: Re: load average with multi-core CPU's On 9/22/11 10:59 PM, Rodrigo Gonzalez wrote: On 09/22/2011 04:29 PM, Mark Felder wrote: On Thu, 22 Sep 2011 10:22:43 -0500, Henry M henr...@gmail.com wrote: Hi all, Can someone explain, or point me to correct documentation on what the load average on top/uptime is actually displaying? Load average is average number of processes in the run queue for the 1, 5, and 15 minute intervals. If you have a quad core CPU a 4.00 load average means you've been keeping the CPU busy at 100%. Not exactly as I understand itIO (disk, network or whatever) affects it too... It is the number of task waiting in queue to be runbut IO is important...if 2 processes are waiting for IO and it is completely saturated they will be kept in queue so load will get higher I think there are other things that affect load average but are over my current knowledge... Regards Rodrigo Gonzalez Actually, I could be wrong but that is the number of tasks both in the waiting *AND* the running queue. It is the average of the number of 'runnable' processes -- those that are actually running (which is -- obviously! -- limited to the number of logical cpu's present) and those that are -- in _all_ other respects -- 'ready' to be run. This list of processes -- 'running' and 'runnable -- is known as the 'run queue'. The cpu 'scheduler' allocated cpu time slots between the processes in the 'run queueu', _only_. Anything -not- in the 'run queue' is not eligible for a slice of cpu time -- because it can't use cpu time, if it were to be offered, because it is 'waiting' on something else. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
load average with multi-core CPU's
Hi all, Can someone explain, or point me to correct documentation on what the load average on top/uptime is actually displaying? Is the load the average amount of processes waiting to execute on the server, or is it independent of CPU? Am I correct with the below statements? * Example 1: 1 CPU, load average of 1.00, CPU at capacity. No processes have to wait to execute. 1 CPU, 2.00 load average, 1 process is waiting to execute. * Example 2: 1 CPU, 4 cores. load average of 2.00. 2 cores are working at capacity, other 2 are idle (mostly). 1 CPU, 4 cores, load average 5.00. 4 cores are at capacity, 1 process waiting to execute. I tried searching, but I couldn't find much besides some blog postings. Thanks, Henry ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: load average with multi-core CPU's
On Thu, 22 Sep 2011 10:22:43 -0500, Henry M henr...@gmail.com wrote: Hi all, Can someone explain, or point me to correct documentation on what the load average on top/uptime is actually displaying? Load average is average number of processes in the run queue for the 1, 5, and 15 minute intervals. If you have a quad core CPU a 4.00 load average means you've been keeping the CPU busy at 100%. Does that make sense? Regards, Mark ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: load average with multi-core CPU's
Thanks- That's what I thought it was. I'm trying to settle an argument at work : ) On Thu, Sep 22, 2011 at 3:29 PM, Mark Felder f...@feld.me wrote: On Thu, 22 Sep 2011 10:22:43 -0500, Henry M henr...@gmail.com wrote: Hi all, Can someone explain, or point me to correct documentation on what the load average on top/uptime is actually displaying? Load average is average number of processes in the run queue for the 1, 5, and 15 minute intervals. If you have a quad core CPU a 4.00 load average means you've been keeping the CPU busy at 100%. Does that make sense? Regards, Mark __**_ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/**mailman/listinfo/freebsd-**questionshttp://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-** unsubscr...@freebsd.org freebsd-questions-unsubscr...@freebsd.org ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
Re: load average with multi-core CPU's
On 09/22/2011 04:29 PM, Mark Felder wrote: On Thu, 22 Sep 2011 10:22:43 -0500, Henry M henr...@gmail.com wrote: Hi all, Can someone explain, or point me to correct documentation on what the load average on top/uptime is actually displaying? Load average is average number of processes in the run queue for the 1, 5, and 15 minute intervals. If you have a quad core CPU a 4.00 load average means you've been keeping the CPU busy at 100%. Not exactly as I understand itIO (disk, network or whatever) affects it too... It is the number of task waiting in queue to be runbut IO is important...if 2 processes are waiting for IO and it is completely saturated they will be kept in queue so load will get higher I think there are other things that affect load average but are over my current knowledge... Regards Rodrigo Gonzalez ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to freebsd-questions-unsubscr...@freebsd.org
