heh, sorry, but your article just says exactly what I just said. So apparently you haven't even read it. Load average does NOT tell you anything about CPU usage, not as far as amount used / amount idle is concerned. As I just said. Also as I just said, even a load average as high as 5 on a single CPU doesn't mean you need a faster CPU, because a load average as high as 5 on a single CPU can still have 80% idle CPU time. Load average doesn't tell you anything about percentage of CPU usage. Only tells you how many active processes are actively using up *some* CPU time, without actually telling you *how much* CPU time is getting used. Your article states the exact same thing. As does the man pages for 'top' if you bothered to read them. If you had 25 processes that each constantly used up 2% of your CPU then you would get a load average of 25. 25 processes, 25 load average. And you'd still have 50% of your CPU time left over for additional workload. Load average is a good detail to know about your machine, but it definitely doesn't tell you much about CPU usage.
On 6/25/05, kama <[EMAIL PROTECTED]> wrote: > On Fri, 24 Jun 2005, Clayton Macleod wrote: > > > You are contradicting yourself or you have a scew picture of what load is. > You are first talking about "how many processes were competing" and then > you write "all that tells you is that in the last minute there was an > average of 5.2 processes each using *some* CPU time at once." Which is not > the same thing and is not really the truth. > > The correct desription of load is more like: > > Load: An average of how many processes that where in queue for getting > kernel resources. > > Have a look at http://www.hostpronto.com/article/36 for more info on UNIX > load. > > > This is also not really true. You will get a good look how much each > virtual processor uses. At least in FreeBSD. In FreeBSD 5.x you can do a > simple 'ps aux | grep idle' and get how much idle each virtual processor > has. Also all the %CPU usage in top and ps for a process only shows on a > virtual CPU, so in theory you can have 4 processes using 99.999% CPU > without hitting the roof. > > But I agree, he should try to disable HT. In theory you will get an > performance boost, since the SMP will now only need to have to know about > 2 instead of 4 CPU's. You also is not bound to half the CPU power for the > process. So if a process needs to have more than what a HT CPU can offer, > it will then get that without hitting the roof. > > The only reason I can see why you should have HT enabled is that if one > process hangs and start using up 100% of CPU, you still have 75% of the > total cpu power left to work with instead of 50%. But if that happens on a > gameserver, you probably jump to the server directly to fix it anyway. > > There is also a bug in the HT that allows in certain circumstances to read > data from other processes. Due to this bug, FreeBSD now have HT disabled > by default. You need to switch it on with a sysctl variable. > > If I could I would have switched of HT on all my servers. But due to a > bug in FreeBSD, it will not boot up. I get some strange IDE timeouts at > bootup. Perhaps upgrading from 5.3 to 5.4 will solve it. > > /Bjorn -- Clayton Macleod _______________________________________________ To unsubscribe, edit your list preferences, or view the list archives, please visit: http://list.valvesoftware.com/mailman/listinfo/hlds_linux
