-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Eric,
On 9/10/20 15:29, Eric Robinson wrote: > Chris -- > > >> You should also look at worker-thread availability. When you see >> these "high latency" (which is usually a term reserved for I/O >> characterization) events, do you have:>> 1. Available worker >> threads (from the executor thread pool) 2. Any other >> shared/limited resource (e.g. DB connection pool) >> > > Good thought. I should mention that the hosted application is > canned, and is the same for all tomcat instances, with only minor > variations in version between them. User workflow is also similar. > Over the years we've developed a good feel for expected > performance and resource utilization based on the user count per > instance. So when one instance exhibits anomalous performance, we > tend to go right to networking issues. > >> Also, are you seeing the otherwise unexpected slowness on each >> Tomcat node, or are you seeing it at the >> load-balancer/multiplexer level? >> > > We run multi-tenanted servers, with many instances of tomcat on > each server. We've never seen issues at the load-balancer. What I mean is, are you measuring the request at the Tomcat level, or at the load-balancer level? If you are watching at the lb, then your lb might pick a "busy" Tomcat and the request has to "wait in line" before processing even begins. If you sample at the Tomcat level, you'll see no discernible slowdown because the time "waiting in line" does not count. > Very occasionally, there might be a problem at the server level. > When that happens, all instances on that server may become > sluggish. What I'm talking about in this thread are cases where > only one instance on a server is showing slowness in its jasper > logs. Also, we typically do not see the same slowness when we test > the application locally from the same network. I've had my eye on > TCP retransmits as a possible culprit for a while, but I just > didn't know for sure if my understanding of the tomcat processing > timer is correct. I hope we've cleared that up for you, then. You might also want to read about "buffer bloat" if you aren't already familiar with that term. - -chris -----BEGIN PGP SIGNATURE----- Comment: Using GnuPG with Thunderbird - https://www.enigmail.net/ iQIzBAEBCAAdFiEEMmKgYcQvxMe7tcJcHPApP6U8pFgFAl9aiH4ACgkQHPApP6U8 pFiFfBAAvuUbRXK+iDDy7lLsw6eplMFrXXDbkxzwtSNafvdGlDWmcPWwdazZwhQ+ TJ0pzkUwf3/RBslu/oORJYelYKhpUJLodj0Y85ZtbuKBcU2JpKk1uueJ/aqnmVFK 9yep3ReYdggEXQ3JNb1VeI4ASdEhFWoFw8pc6DAcJZ4K2JaUtGKrtoWG8n+oEXos kmthl9Dm9ge3edLimd7TPTx11iODi6pX3ddJ+uRh7qmvXZp4wVyX8W+hkKiOhUQM hokUd8RruXQm6wut5m+JSO6eLHqkKUBiLspzlz1x/Y4cuaqAlC8Pl5y9NFTuLK3e gFJeDmBUthN2y5h9KNKW5r+Gf9bKpuv1+kw7CIaNoFv2JxCGTmfL3VKM+Bp/rh7J 1SbshsTW6ffo5hKRNJUJKvxry3uUvzrss0AYe338tJ1QA+sHuXHsN8ZVtY3b+51O HBOYf3pgIPsSd6zXkjaSRoOAhVc9G5sbJHx8ycQt+yAyVvXEUwrqeeRbsJeADk2s reaizm9WvO2kHSqP93ANNYe1QJ+rw9b5og0uoCE8x9eO+czRHbJ7LFF6/rvX+6Pn TIYB7AHyV8P3PHpHtBGIgaNfnvIYbqx/hzxJpLlpNEcS2zARfi1YCnuNtbiH0KU/ AKkBx5FnZvwclCA3qK2oqBnSEcBUFz2yobq4wAy//qwgL2gEFNc= =mcpm -----END PGP SIGNATURE----- --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
