I'm guessing that strace is showing me userland threads? When I quit strace I see:
^CProcess 19363 detached Process 19364 detached Process 19365 detached Process 19366 detached Process 19367 detached Process 19368 detached Process 19369 detached Process 19370 detached Process 19371 detached Process 19372 detached Process 19377 detached Process 19378 detached Process 19379 detached Process 19380 detached Process 19381 detached Process 19382 detached Process 19383 detached Process 19384 detached Process 19385 detached Process 19386 detached Process 19387 detached Process 19388 detached Process 19389 detached Process 19390 detached Process 19391 detached Process 19392 detached Process 19393 detached Process 19394 detached Process 19395 detached Process 19396 detached Process 19397 detached Process 19398 detached Process 19399 detached Process 19400 detached Process 19401 detached Process 19402 detached Process 19403 detached Process 19404 detached Process 19405 detached Process 19406 detached Process 19407 detached Process 19408 detached Process 19409 detached Process 19410 detached Process 19606 detached % time seconds usecs/call calls errors syscall ------ ----------- ----------- --------- --------- ---------------- 90.06 40.973072 1363 30059 10449 futex 4.23 1.926411 819 2353 epoll_wait 3.02 1.373282 114440 12 6 restart_syscall 1.24 0.563107 93851 6 accept 0.99 0.449988 12 36909 gettimeofday 0.35 0.156992 5 29410 clock_gettime 0.05 0.021064 67 316 recvfrom 0.02 0.010338 30 347 write 0.01 0.005117 24 209 sendto 0.01 0.004369 24 180 poll 0.01 0.002683 24 112 22 read 0.01 0.002563 24 108 6 epoll_ctl 0.00 0.001618 14 112 open 0.00 0.001189 5 230 fcntl 0.00 0.001132 8 142 mprotect 0.00 0.000969 8 118 close 0.00 0.000806 38 21 writev 0.00 0.000685 6 109 ioctl 0.00 0.000655 6 110 fstat 0.00 0.000229 13 17 mmap 0.00 0.000216 36 6 shutdown 0.00 0.000197 33 6 dup2 0.00 0.000092 46 2 madvise 0.00 0.000061 5 12 setsockopt 0.00 0.000057 14 4 munmap 0.00 0.000056 5 12 getsockname 0.00 0.000035 4 8 rt_sigprocmask 0.00 0.000018 5 4 sched_getaffinity 0.00 0.000010 5 2 clone 0.00 0.000009 9 1 rt_sigreturn 0.00 0.000009 5 2 uname 0.00 0.000009 5 2 set_robust_list 0.00 0.000008 4 2 gettid ------ ----------- ----------- --------- --------- ---------------- 100.00 45.497046 100943 10483 total On Tuesday, September 23, 2014 9:44:52 PM UTC-4, larry google groups wrote: > > I am intrigued by this article, as the problem sounds the same as mine: > > http://corner.squareup.com/2014/09/logging-can-be-tricky.html > > "No significant amount of resources appeared to be in use — disk I/O, > network I/O, CPU, and memory all looked fairly tame. Furthermore, the bulk > of queries being served were all performing as expected. " > > So I tried to follow their example regarding strace. But I have never > worked with strace before. I used grep to find the PID and then I: > > sudo strace -c -f -p 19363 > > and I got: > > Process 19363 attached with 45 threads > > Then I ran our "health check" which is like a series of functional tests > that ping our actual app (a live environment rather than a test > environment). I got nothing out of strace except these 2 lines appeared: > > Process 20973 attached > Process 20974 attached > > What does this mean? I had the impression that the JVM ran in 1 process? > Does strace show me userland threads (like htop does) or are these child > processes? > > > > > > On Monday, September 15, 2014 12:15:14 AM UTC-4, larry google groups wrote: >> >> >> I have an embarrassing problem. I convinced my boss that I could use >> Clojure to build a RESTful API. I was successful in so far as that went, >> but now I face the issue that every once in a while, the program pauses, >> for a painfully long time -- sometimes 30 seconds, which causes some >> requests to the API to timeout. We are still in testing, so there is no >> real load on the app, just the frontenders, writing Javascript and making >> Ajax calls to the service. >> >> The service seems like a basic Clojure web app. I use Jetty as the >> webserver, and the libraries in use are: >> >> Ring >> >> Compojure >> >> Liberator >> >> Monger >> >> Timbre >> >> Lamina >> >> Dire >> >> When someone complains about the pauses, I will go test the service, and >> I can hit with 40 requests in 10 seconds and it has great performance. The >> pauses actually seem to come after periods of inactivity, which made me >> think that this had something to do with garbage collection, except that >> the pauses are so extreme -- like I said, sometimes as much as 30 seconds, >> causing requests to timeout. When the app does finally start to respond it >> again, it goes very fast, and responds to those pending request very fast. >> >> But I have to find a way to fix these pauses. >> >> Right now I packaged the app as an Uberjar and put it on the server, spun >> it up on port 24000 and proxied it through Apache. I put a script in >> /etc/init.d to start the app using start-stop-daemon. >> >> Possible things that could be going wrong: >> >> Maybe Jetty needs more threads, or maybe less threads? How would I test >> that? >> >> Maybe the link to MongoDB sometimes dies? (Mongo is on another server at >> Amazon) How would I test that? >> >> Maybe it is garbage collection? How would I test that? >> >> Maybe I have some code that somehow blocks the whole app? Seems unlikely >> but I'm trying to keep an open mind. >> >> Maybe the thread pool managed by Lamina sometimes gets overwhelmed? How >> would I test that? >> >> Maybe when Timbre writes to the log file it causes things to pause? (But >> I believe Timbre does this in its own thread?) How do I test that? >> >> This is a small app: only about 1,100 lines of code. >> >> I don't have much experience debugging problems on the JVM, so I welcome >> any suggestions. >> >> >> >> >> >> >> >> -- 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.
