[opensuse] how to figure out, where is the bottleneck
Hi, I've three subsystems of a complex software architecture running on one host with 16CPU's, when the system runs under load, top shows me that the load goes up to 40 and more, but I think a good value should be sth. between 16 and 20, and I have the fear, that the box at some point becomes more busy with context switching than with the jobs I give to it. top shows me that at least, the box is not swapping. The output of iostat tells me, that the problem is not waiting for IO, so the values there, are not unusually high. Maybe I've just too many processes running at the same time? But before I want to touch the system, and make changes, I'd really make sure I found the bottleneck, at least with the tools mentioned above, I've no real clue yet. Any recommendation to other tools, I could run, or files to check, to monitor the system when it is under high load? kind regards Sebastian -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
On Tue, Aug 12, 2008 at 9:36 AM, Sebastian Reitenbach
Hi,
I've three subsystems of a complex software architecture running on one host with 16CPU's, when the system runs under load, top shows me that the load goes up to 40 and more, but I think a good value should be sth. between 16 and 20, and I have the fear, that the box at some point becomes more busy with context switching than with the jobs I give to it. top shows me that at least, the box is not swapping. The output of iostat tells me, that the problem is not waiting for IO, so the values there, are not unusually high.
Maybe I've just too many processes running at the same time? But before I want to touch the system, and make changes, I'd really make sure I found the bottleneck, at least with the tools mentioned above, I've no real clue yet. Any recommendation to other tools, I could run, or files to check, to monitor the system when it is under high load?
kind regards Sebastian
But is it fast? You mention only the numbers, not the thru-put. Is it doing the job?You On a busy machine doing lots of work its not unreasonable for there to be two or three tasks waiting per thread. If you have lots of processors chances are it just gets busier. You can set affinity of each of these tasks giving them one or two processors to run on, but usually the system does a better job of that than you could. Are these three tasks waiting for each other? -- ----------JSA--------- Someone stole my tag line, so now I have this rental. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
Sebastian Reitenbach wrote:
Hi,
I've three subsystems of a complex software architecture running on one host with 16CPU's, when the system runs under load, top shows me that the load goes up to 40 and more, but I think a good value should be sth. between 16 and 20, and I have the fear, that the box at some point becomes more busy with context switching than with the jobs I give to it. top shows me that at least, the box is not swapping. The output of iostat tells me, that the problem is not waiting for IO, so the values there, are not unusually high.
Maybe I've just too many processes running at the same time?
I don't think the number of processes ready to run is a _really_ good performance indicator. At least you need to look at CPU saturation as well. As long as your CPUs aren't running flat out, I think you'll be fine.
But before I want to touch the system, and make changes, I'd really make sure I found the bottleneck, at least with the tools mentioned above, I've no real clue yet.
How do you know that you have a bottleneck at all? Is your system not sufficiently responsive? /Per Jessen, Zürich -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
participants (3)
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John Andersen -
Per Jessen -
Sebastian Reitenbach