I know that remembering to put "-server" used to be a huge issue, but I thought that on all recent versions of Java on all modern 64-bit machines, -server is now the default. I thought it was a non-issue at this point. Is that incorrect?
On Thu, May 14, 2015 at 1:54 PM, Colin Yates <colin.ya...@gmail.com> wrote: > 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. > 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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