number locusts must be a multiple of the number of slaves

[sanga]

We have 80 slaves in our set up and this is somewhat restrictive at times i.e. at times it would be nice step in finer jumps than 80 (of course I could kill some slaves, but that's a bit clunky)

[heyman]

Ah, I see.

The reason for the current behaviour is just simplicity/laziness (easier to just order each slave to spawn the same number of locust users) and I think I was reasoning that when you have a really high number of slave machines, you're likely to also have them run many more magnitudes of locust users so it shouldn't matter.

However, it shouldn't be very hard to modify the code in MasterLocustRunner.start_hatching (

locust/locust/runners.py

Line 262 in 01ecb04

def start_hatching(self, locust_count, hatch_rate):

) to make it either not use all slaves if the number of users < number of slaves. Or if users > slaves but users aren't an even multiple of slaves, distribute the number of users as evenly as possible, but not the same amount to each slave. I also think that would be an improvement :).

[Jahaja]

Fixed in the commit referenced above.

I just distributed the remaining locusts by adding one locust for each slave until theres no more locusts left to distribute.

[sanga]

Just got around to having a look at this afternoon. Thanks for the speedy fix!

[heyman]

Great!

I found a small bug when testing this out. If one tried to spawn fewer locusts than the number of connected slaves, we would still spawn one user per slave. I've fixed this is fb2bd53. It's a one line fix and ~20 lines test, plus two other tests I wrote while debugging it :).

[Jahaja]

Excellent!

[sanga]

yeah, I spotted that too but figured I'd have a go at fixing it rather than complaining about a (somewhat) nitpicky thing. Thanks for beating me to it ;)

[sanga]

Actually this still looks a little broken in current master. I've seen that at least the number of locusts can overrun what you ask for. I'll do a bit more digging today if I can dig out the root cause or at least narrow it down a bit.

[abhimanyuPlivo]

Is this issue still persisting? I have 16 Slaves in my setup and have 30 different types of users defined. Seems like the minimum load I can run is with 16 * 30 = 480 locusts.

[wreed4]

This is definitely still an issue for me, but it doesn't seem as clear cut. I was running with 10 slaves, 100 Locust classes in my locustfile (because I need to hit 100 different hosts) and the minimum number of users I can run with is 501. 500 or less spawns zero users. It might also have to do with the spawn rate. The logs of each slave say "spawning 0 clients with hatch rate of 0.2 cl/sec" or something similar.