Re: [gentoo-user] 100% CPU usage with no processes to blame?
On Saturday 17 February 2007, Alex Schuster wrote: Shouldn't top have provided some kind of info for why the CPU usage was 100% for 5 minutes straight? If it does display trends, shouldn't it have picked up on that one? I bet it was updatedb. This is what top shows me when it is running: or eupdatedb, or prelink... :-) Cpu(s): 15.6% us, 12.6% sy, 0.3% ni, 0.0% id, 70.2% wa, 1.3% hi, 0.0% si PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1563 root 18 0 1936 928 528 R 8.9 0.2 0:09.68 updatedb Whatever this wa entry is, probably something with I/O related waiting, it seems is it not being taken into account for the %CPU culumn entry of the process. wa is wait - a process is trying to do IO and it is being blocked as something else is using a resource the process wants to use. SO it sits and does nothing, much the same way you sometimes sit in your car and do nothing at the McDonalds drive-through queue. Usually a blocked process will consume no cpu time (as it's doing nothing), but it can slow the machine down and make it less responsive while many processes sit and wait alan -- Optimists say the glass is half full, Pessimists say the glass is half empty, Developers say wtf is the glass twice as big as it needs to be? Alan McKinnon alan at linuxholdings dot co dot za +27 82, double three seven, one nine three five -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] 100% CPU usage with no processes to blame?
On Thursday 15 February 2007 22:02, b.n. wrote: Michael Crute ha scritto: You should use ps, top and free of course! Just realize that they lie... Seeing this thread reminded me of a blog article I saw on Virtual Threads a while back... http://virtualthreads.blogspot.com/2006/02/understanding-memory-usage-on- linux.html He does a pretty good job of explaining where top gets its numbers and how to properly interpret them. HTH Nice post. Thanks for the link. Indeed, I hadn't used the pmap command until now! I was shocked to discover the direct memory used by Firefox-bin vs Opera vs Konqueror (just for a laugh). -- Regards, Mick pgpPobrx6MqK2.pgp Description: PGP signature
Re: [gentoo-user] 100% CPU usage with no processes to blame?
Grant writes: Shouldn't top have provided some kind of info for why the CPU usage was 100% for 5 minutes straight? If it does display trends, shouldn't it have picked up on that one? I bet it was updatedb. This is what top shows me when it is running: Cpu(s): 15.6% us, 12.6% sy, 0.3% ni, 0.0% id, 70.2% wa, 1.3% hi, 0.0% si PID USER PR NI VIRT RES SHR S %CPU %MEMTIME+ COMMAND 1563 root 18 0 1936 928 528 R 8.9 0.2 0:09.68 updatedb Whatever this wa entry is, probably something with I/O related waiting, it seems is it not being taken into account for the %CPU culumn entry of the process. I think whis was different with kernel 2.4, it did not show such a high load, while performing similar as now when updatedb was running. Alex -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] 100% CPU usage with no processes to blame?
On 2/15/07, Alan McKinnon [EMAIL PROTECTED] wrote: On Wednesday 14 February 2007, brullo nulla wrote: Most likely you only looked at user cpu % and neglected to list the system and niced times as well. p.s. golden rule: ps lies. top lies. free lies. Don't believe the readings they give, rather interpret them in context. sob. it's not the first time I hear this. What should I believe to really know my system state? You should use ps, top and free of course! Just realize that they lie... Seeing this thread reminded me of a blog article I saw on Virtual Threads a while back... http://virtualthreads.blogspot.com/2006/02/understanding-memory-usage-on-linux.html He does a pretty good job of explaining where top gets its numbers and how to properly interpret them. HTH -mike -- Michael E. Crute http://mike.crute.org God put me on this earth to accomplish a certain number of things. Right now I am so far behind that I will never die. --Bill Watterson -- gentoo-user@gentoo.org mailing list
[gentoo-user] 100% CPU usage with no processes to blame?
I just sat through about 5 minutes of 100% CPU usage and a thrashing hard disk. I ran top and it reported 0% idle CPU, but the list of processes totaled maybe 20% CPU usage. How can this be? - Grant -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] 100% CPU usage with no processes to blame?
On Wednesday 14 February 2007, Grant wrote: I just sat through about 5 minutes of 100% CPU usage and a thrashing hard disk. I ran top and it reported 0% idle CPU, but the list of processes totaled maybe 20% CPU usage. How can this be? - Grant Most likely you only looked at user cpu % and neglected to list the system and niced times as well. p.s. golden rule: ps lies. top lies. free lies. Don't believe the readings they give, rather interpret them in context. alan -- Optimists say the glass is half full, Pessimists say the glass is half empty, Developers say wtf is the glass twice as big as it needs to be? Alan McKinnon alan at linuxholdings dot co dot za +27 82, double three seven, one nine three five -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] 100% CPU usage with no processes to blame?
Most likely you only looked at user cpu % and neglected to list the system and niced times as well. p.s. golden rule: ps lies. top lies. free lies. Don't believe the readings they give, rather interpret them in context. sob. it's not the first time I hear this. What should I believe to really know my system state? m. -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] 100% CPU usage with no processes to blame?
On 14 February 2007 18:55, Alan McKinnon wrote: On Wednesday 14 February 2007, Grant wrote: I just sat through about 5 minutes of 100% CPU usage and a thrashing hard disk. I ran top and it reported 0% idle CPU, but the list of processes totaled maybe 20% CPU usage. How can this be? - Grant Most likely you only looked at user cpu % and neglected to list the system and niced times as well. p.s. golden rule: ps lies. top lies. free lies. Don't believe the readings they give, rather interpret them in context. !!! Golden rule of system administration: All these tools are notoriously wrong. Uwe -- A fast and easy generator of fractals for KDE: http://www.SysEx.com.na/iwy-1.0.tar.bz2 Proof of concept of a TSP solver for KDE: http://www.SysEx.com.na/epat-0.1.tar.bz2 -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] 100% CPU usage with no processes to blame?
On Mittwoch, 14. Februar 2007, brullo nulla wrote: Most likely you only looked at user cpu % and neglected to list the system and niced times as well. p.s. golden rule: ps lies. top lies. free lies. Don't believe the readings they give, rather interpret them in context. sob. it's not the first time I hear this. What should I believe to really know my system state? youc ould try htop. Maybe it lies a little bit less than top. -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] 100% CPU usage with no processes to blame?
On Wednesday 14 February 2007 12:25:27 pm brullo nulla wrote: Most likely you only looked at user cpu % and neglected to list the system and niced times as well. p.s. golden rule: ps lies. top lies. free lies. Don't believe the readings they give, rather interpret them in context. sob. it's not the first time I hear this. What should I believe to really know my system state? m. I tracked my 100% cpu usage to FAMD... Killing it instantly freed the cpu... -- -- Jerry McBride -- gentoo-user@gentoo.org mailing list
RE: [gentoo-user] 100% CPU usage with no processes to blame?
-Original Message- From: Hemmann, Volker Armin [mailto:[EMAIL PROTECTED] Sent: Wednesday, February 14, 2007 1:14 PM To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] 100% CPU usage with no processes to blame? On Mittwoch, 14. Februar 2007, brullo nulla wrote: Most likely you only looked at user cpu % and neglected to list the system and niced times as well. p.s. golden rule: ps lies. top lies. free lies. Don't believe the readings they give, rather interpret them in context. sob. it's not the first time I hear this. What should I believe to really know my system state? youc ould try htop. Maybe it lies a little bit less than top. -- gentoo-user@gentoo.org mailing list If I cannot trust the tools provided by the OS for finding out whats going on-- than what can I trust -- this is intolerable! - if it is simply a situation if a non root user not being able to see root processes that is one thing, BUT if it really is a situation of the tools not giving accurate asessments, that is a whole other situation, and one that just cannot be allowed to continue (not that I can do much other than scream about it, cuz im not a programmer) Tim Holmes IT Manager / Webmaster / Teacher Medina Christian Academy A Higher Standard... -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] 100% CPU usage with no processes to blame?
Hi, On Wed, 14 Feb 2007 13:31:31 -0500 Timothy A. Holmes [EMAIL PROTECTED] wrote: If I cannot trust the tools provided by the OS for finding out whats going on-- than what can I trust -- this is intolerable! - if it is simply a situation if a non root user not being able to see root processes that is one thing, BUT if it really is a situation of the tools not giving accurate asessments, that is a whole other situation, and one that just cannot be allowed to continue (not that I can do much other than scream about it, cuz im not a programmer) It's mainly not a matter of trust, it's a matter of definitions not meeting expectations. From an objective POV, the measures shown are correct. They are just defined as a more or less complex computation which isn't exactly what is expected subjectively. People tend to ignore the definitions and imagine the meaning from the shortened name of the shown value. Regarding trusting the OS: Those tools don't come with the kernel. This is Linux, not the BSDs. -hwh -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] 100% CPU usage with no processes to blame?
2007. 02. 14, szerda keltezéssel 13.28-kor Jerry McBride ezt írta: I tracked my 100% cpu usage to FAMD... Killing it instantly freed the cpu... Change to gamin. The same function in much better. I did it about a year ago. (Or less, I don't remember). It solved me some other problems (CD lock down etc.) In the gentoo documents you can find article about how to change it. Regards, István -- Nyílt forráskód azokra az igazán nehéz napokra. BSA Open source for those really hard days. BSA http://www.osbusiness.hu -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] 100% CPU usage with no processes to blame?
On Wednesday 14 February 2007 02:48:18 pm Pongrácz István wrote: 2007. 02. 14, szerda keltezéssel 13.28-kor Jerry McBride ezt írta: I tracked my 100% cpu usage to FAMD... Killing it instantly freed the cpu... Change to gamin. The same function in much better. I did it about a year ago. (Or less, I don't remember). It solved me some other problems (CD lock down etc.) In the gentoo documents you can find article about how to change it. Thank you, for the tip. I never would have found it, without your help. Cheers. -- Jerry McBride -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] 100% CPU usage with no processes to blame?
On Mittwoch, 14. Februar 2007, Jerry McBride wrote: On Wednesday 14 February 2007 02:48:18 pm Pongrácz István wrote: 2007. 02. 14, szerda keltezéssel 13.28-kor Jerry McBride ezt írta: I tracked my 100% cpu usage to FAMD... Killing it instantly freed the cpu... Change to gamin. The same function in much better. I did it about a year ago. (Or less, I don't remember). It solved me some other problems (CD lock down etc.) In the gentoo documents you can find article about how to change it. Thank you, for the tip. I never would have found it, without your help. or just go without it, because both (fam, gamin) are both superfluos -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] 100% CPU usage with no processes to blame?
On Wednesday 14 February 2007, brullo nulla wrote: Most likely you only looked at user cpu % and neglected to list the system and niced times as well. p.s. golden rule: ps lies. top lies. free lies. Don't believe the readings they give, rather interpret them in context. sob. it's not the first time I hear this. What should I believe to really know my system state? You should use ps, top and free of course! Just realize that they lie... Actually they don't lie, they give an average. You also need to understand what is going on. Without getting into the details of exactly what a cpu is doing, it's performing actions millions of times a second. In the time it takes top to update (2 seconds), the kernel could have started and shut down several thousand forked processes. So trying to measure something that changes so fast is a waste of time. Also, there's the kernels internal timer. It's set by default to 100Hz, which means that the kernel updates it's own counters 100 times a second. It's quite possible to use and discard lots of memory in that gap and for it to never even show up in the kernel's counters. Raising the timer frequency for 1000Hz for a desktop gives more accurate results, but they are still just an average. Same with memory - the kernel allocates it out and shares the same memory between several processes as it sees fit. And does what it wants to with swap as well. Again, trying to find out the current state of the system is useless as by the time you read it, it has changed 16 million times When we say that top lies, we really mean that it is giving you an average over a looong period of cpu time, and you should interpret it as such. It's a trend, not an instant value. alan -- Optimists say the glass is half full, Pessimists say the glass is half empty, Developers say wtf is the glass twice as big as it needs to be? Alan McKinnon alan at linuxholdings dot co dot za +27 82, double three seven, one nine three five -- gentoo-user@gentoo.org mailing list
Re: [gentoo-user] 100% CPU usage with no processes to blame?
On Wednesday 14 February 2007, Timothy A. Holmes wrote: If I cannot trust the tools provided by the OS for finding out whats going on-- than what can I trust -- this is intolerable! - if it is simply a situation if a non root user not being able to see root processes that is one thing, BUT if it really is a situation of the tools not giving accurate asessments, that is a whole other situation, and one that just cannot be allowed to continue (not that I can do much other than scream about it, cuz im not a programmer) Calm down, the tools are not outright lying, see my other reply to brullo for details. The trend the tools display is accurate though. Incidentally, you do realize that every OS written in the past 20 years suffers from this exact same problem, right? Linux simply doesn't try and hide the fact that it is lying -- Optimists say the glass is half full, Pessimists say the glass is half empty, Developers say wtf is the glass twice as big as it needs to be? Alan McKinnon alan at linuxholdings dot co dot za +27 82, double three seven, one nine three five -- gentoo-user@gentoo.org mailing list
