On 31 May 2013, at 11:26, Norbert Hartl <norb...@hartl.name> wrote: > > Am 27.05.2013 um 10:17 schrieb p...@highoctane.be: > >> I was looking at the output of "top" for while and Pharo was trusting the >> top spot indeed. >> >> Well, I'll look at all that this evening and give back the impressions. >> >> I want to run several instances of Pharo on the box and it will for sure add >> up. Say, 20 x 2% gives an awful lot. >> > What is the use of having 20 idle images on one server? :) I think you can't > easily say that it always adds on top. If your image is running at 100% the > 2% off even if fully countable wouldn't be that much. But nevertheless it is > a valid point and I cannot see pharo becomes more modern by stop polling in > the mid-term future. > Anyway I played a little bit with the tweaks and there are things that make > me wonder. I raised the limit for server mode but didn't get much benefit. > Having a cycle pause of 100ms in serverMode and stopping the ui process still > gave me a 1% CPU usage which is really a lot. Does anyone know in-depth what > an image is doing? How to investigate? Maybe there are a lot of native > polling things involved, too? > I need to dig deeper.
Killing as much non-needed process is certainly step one. A clean image has these processes: 1. Delay scheduling process 2. Input events fetching process 3. The low space watcher 4. The weak array finalization process 5. Morphic UI process 6. The idle process So you killed 5. How did you do that exactly ? Is #serverMode still relevant when 5 is gone ? Would it be possible to kill 2 ? Is it needed for a headless server ? As long as file and socket IO keeps working, we're good. The rest is probably all needed. Are there any (slightly busy) processes inside the VM that we can't see at the Smalltalk level ? > Norbert > >> Phil >> >> >> On Mon, May 27, 2013 at 10:07 AM, Norbert Hartl <norb...@hartl.name> wrote: >> >> Am 27.05.2013 um 09:49 schrieb Sven Van Caekenberghe <s...@stfx.eu>: >> >>> BTW, load & cpu usage numbers can be very hard to interpret. >> >> really? CPU usage is pretty easy and you can see this in most OSses >> directly. 100% CPU usage is full :) Load isn't that much harder. It's just >> the load of the scheduler queue. So if some needs a rule of thumb >> >> safe CPU load = number of cores/processes * 0.7 >> theoretical optimal CPU load = number of core/processes >> >> Everything above should really be investigated because you entered the zone >> where additional CPU load can drive your machine unresponsive. >> You have less CPU usage but high load? Investigate I/O usage! >> >> I know you know that, Sven. I just wanted to mention it because this comes >> up from time to time. Compared to memory consumption, CPU, scheduler and I/O >> are easier targets IMHO. >> >> For Phil the point isn't the health of the system. It is EC2. You have to >> pay for the CPU usage on EC2 so I think he had the impression there is room >> for improvement. And indeed there is. But if you calculate it through it >> isn't really a factor. >> >> Norbert >> >> >
