gpnsatan

gpnsatan

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Distributed sim slowness?? Feb. 4, 2016, 2:07 p.m.

I'm aware of more cores/GHz are better then combined.
But in my test case, my machine is 12 cores, all dist sim machines are either 8 cores or 12 cores(actually 2 8 cores and 2 12 cores, they all have same 48G ram), the only difference is my workstation is better version Xeon, while the 8 cores might be a i7 with hyper thread. Cause I want to see how the load balance work.

I thought that only particles on boundary are transferred not everything(cause when I check tracker output, transfer only take miliseconds, and maybe up to seconds, with 240 frame this only takes minutes total out of entire simulation.)

If dist sim is intended to just make sure over sized sim can actually be simed, then I think it still need to be worked on.(cause the tank_initial is actually taking up quite a lot of time as well even sim on a single machine.(if not using flat tank)

Distributed sim slowness?? Feb. 3, 2016, 5:12 p.m.

Just to pop a question here, I setup a small queue and run a distributed sim using the master class video as my guide, it ran well but it is very slow compare to simulate the sim on a single machine.

From 1 ~ 16million(runs for 23 hours) particles, where the 16m sim runs about 20minutes for 10 frame(out of 240, so it will run about 8 hours on single machine). It is true that the machines run distributed sim is a bit slower than my workstation but still it's quite slow when you have 4 slower machines stack up to run one sim.

Is there a threshold in particle counts that distributed sim start to show advantage?(cause 1m sim is about 10x slower, while 16m sim seems to be only 3x slower) Or is there something wrong in my setup?

Note, this is for the fluid sim only, no white water sim.

HQueue sim CPU usage... Feb. 1, 2016, 5 p.m.

the master class does limited the cpu to 12(according to their machine spec). But however, this does not solve the issue. From what I can see when I do my test(might post another thread) distributed sim is very slow compare to a single machine if it's below certain threshold(say even at 15m particles it's still slower to run sim distributed), this is build 15.0.347.

Also, master class do have a part that Jeff walk through how to also limit the tank_initial part, so make sure you also use that to reduce memory usage.