Probably not helpful, but I tend to rely on the jvm optimisations and just -server. I figured this is an area where a little knowledge is a dangerous thing.
At the very least I would have a realistic benchmark suite to prove to myself that these gains were worth it. In my experience the performance bottleneck is always in design. Just my 2p, although with my self-confessed ignoramus status it is more like 0.5p :). On 14 May 2015 21:46, "Lee Spector" <lspec...@hampshire.edu> wrote: > I'd like to get more guidance on how to specify :jvm-opts for maximum > performance. I've received some help on this topic from people on this list > in the past (thanks!), but I'm pretty sure that I'm still not doing things > right. > > I'm almost always interested in maximum performance for long-running, > compute-intensive and memory-intensive processes, almost never caring much > at all about startup time or anything else. > > I also run my code on different machines, with different numbers of cores > and amounts of memory, and would prefer to be able to put something in my > project.clj that will do something reasonable regardless of what machine > it's running on. > > I run my code with "lein run", and I'd like whatever I need to "run fast" > to be in project.clj. > > I don't know a lot about JVM options, and I've tried to figure out what to > specify for :jvm-opts by asking questions here and web searches, but I'm > not at all confident that I'm doing it right yet. And because my systems > are also stochastic, it's not easy for me to do timing tests on the options > I've tried. > > I think there are options relevant to memory and also garbage collection > and maybe also compilation... and what else? I wish there was a simple > switch to get maximum performance of the sort I've outlined here (or at > least a reasonable stab at it), but I gather that there isn't. > > Anyway, here's what I've been using recently, which just deals with memory > and GC (and maybe not in the best way): > > :jvm-opts ~(let [mem-to-use (long (* (.getTotalPhysicalMemorySize > > (java.lang.management.ManagementFactory/getOperatingSystemMXBean)) > 0.8))] > [(str "-Xmx" mem-to-use) > (str "-Xms" mem-to-use) > "-XX:+UseG1GC"]) > > After seeing Alex's post I thought that maybe I should add "-server", as > follows: > > :jvm-opts ~(let [mem-to-use (long (* (.getTotalPhysicalMemorySize > > (java.lang.management.ManagementFactory/getOperatingSystemMXBean)) > 0.8))] > [(str "-Xmx" mem-to-use) > (str "-Xms" mem-to-use) > "-XX:+UseG1GC" > "-server"]) > > Is that right? Does it make sense? What does "-server" do? Also, should I > also be using "^:replace"? > > I've looked in > https://github.com/technomancy/leiningen/blob/master/sample.project.clj > in hopes that this would say more about this stuff, but it doesn't say > anything about -server or ^:replace. > > Looking into the compilation options, it looks from > https://github.com/technomancy/leiningen/wiki/Faster that I should be > specifying: > > :jvm-opts ^:replace [] > > This is also familiar to me from some earlier discussions. But how would I > combine this with the memory/GC/server(?) options above? > > A guess would be that maybe I should do this: > > :jvm-opts ^:replace > ~(let [mem-to-use (long (* (.getTotalPhysicalMemorySize > > (java.lang.management.ManagementFactory/getOperatingSystemMXBean)) > 0.8))] > [(str "-Xmx" mem-to-use) > (str "-Xms" mem-to-use) > "-XX:+UseG1GC" > "-server" > "-XX:-TieredCompilation"]) > > Note that this guess involves changing a + to a - in the last line, which > was suggested for the opposite purpose at > https://github.com/technomancy/leiningen/wiki/Faster -- but I don't know > if it's legitimate. > > Is this a reasonable thing to do to get maximum performance for > long-running, compute-intensive and memory-intensive processes? > > Is the tiered compilation thing maybe already done by including "-server"? > > I'm probably at least somewhat confused about several different issues > here... > > Any help or pointers would be appreciated. > > Thanks, > > -Lee > > > > > > On May 14, 2015, at 3:47 PM, Alex Miller <a...@puredanger.com> wrote: > > > > Gah. Meant in project.clj: > > > > :jvm-opts ^:replace ["-server"] ;; maybe also set max heap with > "-Xmx1g" in there > > > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Clojure" group. 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