On Wed, Oct 2, 2013 at 5:34 AM, Ben Noordhuis <i...@bnoordhuis.nl> wrote: > On Wed, Oct 2, 2013 at 12:48 AM, Kenneth Gunn <k...@161labs.com> wrote: >> Hi! >> >> >> My team is developing a service in node. We are experiencing high CPU >> utilization and are attempting to profile, but are having a hard time >> getting a sufficient picture of what’s going on. We have experience >> profiling in various other environments, but this is our first crack at >> node. >> >> >> We've tried a few different tools (including nodetime.com, which has been >> useful for some things), and have spent most of our time with the v8 >> profiler. The main problem is that our viewable results only cover a small >> portion of the program runtime. More than 80% of the time is spent in >> libc.so, and that time isn't rolled up by function or caller in the node >> program. Also, the C++ section, which I would expect to contain events in >> the v8 interpreter itself, is empty. (Below, I'm including an abbreviated >> output from the v8 tick processor.) > > You need to have the binutils package installed. The tick processor > uses `nm` to map addresses to symbol. > > Small nomenclature nit: V8 is a just-in-time compiler, not an interpreter. > >> We're aware that the v8 profiling output changes frequently, and we've >> managed to figure out how to get the right tick processor version that >> corresponds to the node version we are using. (Our steps are here: >> https://gist.github.com/kennethgunn/6770664 ) We've seen very similar >> results with versions of node ranging from v0.8.9 to v0.10.18. >> >> >> Is libc actually responsible for 80+% of the CPU time? If so, how do we >> roll that up to the the higher level code leading to those calls? Does it >> sound like we're missing something here, or is there another set of tools we >> should consider using? Your help is greatly appreciated! > > That's probably node.js sleeping in the epoll_wait() system call. > Future versions of node.js will filter out such ticks but right now > that's not possible, you have to keep your application busy when > profiling.
Forgot to mention, you can get a reasonable approximation of non-idle time by passing -j or --js to the tick processor. That filters out samples that aren't accountable to JS land. -- -- Job Board: http://jobs.nodejs.org/ Posting guidelines: https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines You received this message because you are subscribed to the Google Groups "nodejs" group. To post to this group, send email to nodejs@googlegroups.com To unsubscribe from this group, send email to nodejs+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nodejs?hl=en?hl=en --- You received this message because you are subscribed to the Google Groups "nodejs" group. To unsubscribe from this group and stop receiving emails from it, send an email to nodejs+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
