Alec Ten Harmsel <alec <at> alectenharmsel.com> writes:
> On Sat, Jun 20, 2015 at 07:03:18PM +0000, James wrote: > > Hello one and all, > > I want to first install Jenkins on a single multicore amd system, so > > I found this brief guide (which seems simple enough): > > https://code.google.com/p/godin-gentoo-repository/wiki/Jenkins > I highly recommend playing with the Jenkins docker container to get a > feel for using the web UI: > docker run -p 8080:8080 -d jenkins > The official jenkins image comes with the bare minimum of libraries so > good luck building any C/C++ project, but it is helpful just to point > and click around (if you already have docker, that is). Yes, I've used Docker on gentoo before. NO, it's currently un-installed and using docker for what I am after only complicates things at this point. > This is not really a fair comparison. Jenkins has no concept of cores, > only "executors". Each executor can run one build at a time. Jenkins was > written with Java in mind (AFAIK), and Java build tools are the reason > for this. `javac` by default launches some number of threads (not sure > how many on other systems, but on my laptop it's usually 3) and compiles > in parallel. I'm not sure it's possible to control this (someone feel > free to correct me if I'm wrong), hence Jenkins does not care about > cores and only about how many builds are allowed to run in parallel at > once. I'll have to drill into javac a bit more, it seems. There is jenkins-bin on gentoo; it should (?) be a quick install and config. I'll keep in mind what you are saying, but my main goal is to find (CI) codes that I can run on gentoo-mesos clusters. Nothing about Jenkins is a critical need for me. Although, as a consultant I do routinely get asked about Jenkins experience, so just noodling around with it a bit is a good idea for me. > So, to the point; when you add more build slaves with more executors, > you will be able to run more builds in parallel and it will therefore be > faster. This gets even more complicated since you can constrain builds > to only run on certain hosts and various other complicated setups, but > in general more executors means more builds in parallel means faster. AT some point, on a single multiprocessor system, Jenkins will slow down even it more resources are configured for it (overall system load, if nothing else)? AT that point, I can note the resources and apply those limits to the cluster and note the performance differences. Surely, a cluster with more resources will be able to do more (CI_Jenkins) work; so discovering those details is a primary goal of this endeavour. > My main suggestion is to not bother running a Jenkins cluster and stick > with a single host setup unless: Sorry, the cluster, is the main_goal, not Jenkins or CI. Buds at cisco are all very braggadocios about CI (Jenkins and others) on their mesos clusters..... > * You are building so many things that utilization is near 100% > * You are targeting multiple platforms and therefore need multiple build > hosts YES, that is exactly the ultimate goal. A CI cluster, open to friends, pals and customers (maybe). It's all about the mesos cluster, you should know that. > P.S. I could not find any reference to parallel, threads, processes or > anything else on javac's man page that makes me think it is easy to set > the number of threads it uses. No surprise there. Configuring threads, cgroups, and memory resources is a hotly contested area of the cluster codes I have (am) working with. Forget bikeshedding, it Blood_shedding....... especially now that RDMA is hotly being pursued by the many. Thanks for your insights, James
