Running on Mac OS X 10.11 with the example on Vapor site, has anyone getting some error when benchmarking with wrk -c128 -1m http://localhost:8080?
Is those error related to a bug Vapor's code or Swift's performance issue for web development? Can it be fix with high priority.
Testing them from Vapor 0.14-0.16.
Some benchmarking tools, especially when they finish, can improperly handle socket closure. Vapor is overly cautious and prints all socket errors it finds (minus a few very common ones).
Most likely this error is nothing to worry about, especially if the application continues to work normally.
Try running a variety of benchmarking applications and the latest version of Vapor (1.1.12 right now) to see if the problem persists. My guess is that it will go away.
Related
We decided to upgrade our website Asp.net core code from .net5 to .net6, we simply set the 'target framework' of the web application to.net6 from .net5. There were no compilation errors, we gave it a test in our development environment and all seemed well.
There were no code changes at all made, and previously the .net5 application has been running for many months without issue (and before that .net framework 4.8).
When we deployed our app to our live production environment, within a few minutes we noticed a slowdown of external calls (calls to https endpoints, often REST-like), we log any calls that take more than 5 seconds, over the space of a few minutes all calls went from slow to timing out (20 seconds).
We are using System.Net.WebClient for all of our calls, which I understand is now obsolete in .net6, however, I would not expect this to suddenly change behavior, and even so, we attempted to change to HttpClient, the recommended approach, with the same results.
I feel like I must be missing something really fundamental, we just upgraded the target framework and redeployed and now all calls made by WebClient eventually timeout.
It feels like a "running out of resources" issue, in code, due to the slow down then timeout, but I am at a loss to explain what is going on here.
To be clear, we are not doing anything special, just calling about 3 external services via WebClient for each user, and we have maybe 100 users a minute at peak, previously, there have been no timeouts.
Any pointers on what might be causing the timeouts would be greatly appreciated.
I guess time will tell if this is the answer, but we changed all of our calls to use DownloadStringTaskAsync and UploadStringTaskAsync, i.e. all calls from blocking to async await, and after 24hrs, we have not seen the same behaviour in our live environment under full load.
Why a web app using .net 5 core would not have these issues but .net 6 would, is hard to understand. For context, we are not under crazy high load, we are talking a peak of perhaps 150 users per minute, but that is what we are seeing.
Perhaps it was something specific to our set up, but I am writing this to save someone else the pain of trying to debug this issue in the future.
That is suspicious and unexpected. If you have HttpClient repro, can you please post it on GitHub https://github.com/dotnet/runtime/issues? (ideally minimal repro we can run locally for debugging)
If your repro is not transferable to another machine, or requires specific endpoints you can't expose, we may have to guide you through some local debugging ...
-Karel (.NET Networking team)
I'm writing an Electron app and a few builds back testers started noticing that two electron.exe processes were consuming a lot of CPU time all the time. One pegging a CPU core and the other using about 85% of a core.
I'm certain that this was not always the case as builds several months ago didn't do this. But I'm at a loss to know how to debug what code changes may have introduced this as the code base has evolved dramatically over that time.
process.getIOCounters() reports that several gigabytes of IO is occurring every few minutes. The application is not deadlocked and everything still works it is just chewing through CPU. It happens anytime the app is open even if it is in the background without any user input. I only have windows 10 x64 systems that I've deployed this to as Electron 1.7.9 and also 1.7.5.
Based on the behavior I'm certain that this IO is interprocess communication between the render and main threads, but I'm not manually performing any IPC. I think this problem is being caused by some module we've introduced that improperly resides in the rendered thread.
My question, how does one debug the The Electron render/main thread IPC pipe? Can it be hooked to know what the contents of the gigabytes of traffic are?
Based on the past few days of attempting to debug this I've answer the question for myself:
My question, how does one debug the The Electron render/main thread IPC pipe?
Don't, electron seemed like a good idea, writing all your client and platform code in the same place. But there are a lot of catches, and out of the blue libraries will have strange bugs that are costly to address because they are outside the main stream use case. This certainly has a lot to do with me not being an Electron Expert, but in the real world there are deadlines and timelines and I can't always get up to speed as much as I would like to.
I've updated my architecture to the tried an true Service/GUI model. I'll be maintaining full browser support for the client code as well as an Electron mode with hooks for some features when electron is detected.
This allows me to quickly identify issues that are specific to browser, version or platform framework. It also lets me use which ever version of NodeJS that I would like to for the service which has also been an issue in my case.
I still love Electron though, I'm just going to be more careful as I use it. If I do discover the specifics of why I had this problem I'll check back and report those details.
Update
So this issue was not directly related to Electron like I had supposed, the IPC was not between the renderer and main threads and was a red herring. It was actually a chrome key frame animation issue which was causing a 60 FPS redraw rate, still not sure why this caused GBs of IPC, but whatever. See https://github.com/Microsoft/vscode/issues/22900
I was able to discover this by porting this app back to native browser ( with nodejs service ). I then ran in chrome, edge and firefox. Only chrome behaved this way.
Website built on: Rails 3.0.3 & Heroku
Installed: Exception Notifier & New Relic
I am rewriting this question since my previous attempt was unclear and subjective, hope this works better.
I have a website where users can perform calculations. Once in a while I get reports from the users through my (one way) communication media that "the website crashes and tells me I need to restart IE, but it still doesn't work" which is pretty much as specific information I have been retrieving.
I get no timestamps so I can not look for it in the logs (Heroku only allows 2000 lines of error logs), I get no exception notifications and I cannot make the error appear myself so I would like your help with the following:
What would make a website crash in the way that it would tell the user to restart the browser? I have never even heard of that! What should I look for in the logs, if I can get timestamps for the errors?
Assuming it is a JavaScript-problem (which seems likely). How could I trouble shoot this issue? What tools can I use? Firebug does not give me any errors.
Assuming it is a IE version thing. How can I test the application in a systematic manner? (without installing/reinstalling different versions). Is there any applications that can test an application for different browsers?
It seems to work for most users/combinations. Do you have an older version of IE installed and can produce this error? Site: www.countcalculate.com (try any calculation).
Probably related to a very intensive loop. For some reason IE thinks it's appropriate to block the UI thread while JavaScript is executing, so the whole thing will freeze up if your JavaScript breaks.
I can't reproduce the issue, so I'd suggest trying to get more detailed reports from your customers.
The problem was (appearantly) limited to IE8 & XP-users. That combination conflicted with a bug in jQuery 1.6.2 according to http://bugs.jquery.com/ticket/9981.
Downgrading to 1.6.1 solved the problem.
I have noticed that after my Grails app has been deployed for about 2 weeks, performance degrades significantly, and I have to redeploy. I am using the Spring Security plugin and caching users. My first inclination is that it has something to do with this and the session cache size, but I'm not sure how to go about verifying this.
Does it sound like I'm on the right track? Has anyone else experienced this and narrowed down the problem? Any help would be great.
Thanks!
Never guess where to optimize, it's going to be wrong.
Get a heap dump and a profile it a little (VisualVM worked fine for me).
It might be a memory leak, like it happened to me. What is your environment - OS, webserver, Grails?
I would recommend getting YourKit (VisualVM has limited information) and use this to profile your application in production (if possible).
Alternatively you could create a performance test (with JMeter for example) and performance test the pieces of your application that you suspect is causing the performance degredation.
Monitoring memory,cpu,threads,gc and such while running some simple JMeter performance tests will definitely find the culprit. This way you can easily re-test your system over time and see if you have incorporated new "performance killing" bugs.
Performance testing tools/services:
JMeter
Grinder
Selenium (Can performance test with selenium grid, need hw though)
Browsermob (Commercial, which uses Selenium + Selenium-Grid)
NeoLoad by NeoTys (Commercial, trial version available)
HP Loadrunner (Commercial, The big fish on the market, trial version available)
I'd also look into installing the app-info plugin and turning on a bunch of the options (especially around hibernate) to see if things are getting out of control there. Could be something that's filling the hibernate session but never closing a transaction.
Another area to look at is if you're doing anything with the groovy template engine. That has a known memory leak, that's sort of unfixable if you're not caching the class/results. Recently fixed a problem around this on our app. If you're seeing any perm gen errors, this could be the case.
Try to install Javamelody plugin. In our case it helped to find problem with GC.
I have done a few projects using Ruby on Rails. I am going to use JRuby on Rails and hosting it on GAE. In that case what are the stuff that I need to know while developing JRuby apps. I read that
JRuby has the same syntax
I can access Java libraries
JRuby does not have access to some gems/plugins
JRuby app would take some time to load for the first time, so I have to keep it alive by sending
request every 5 mins or so
I cannot use ActiveRecord and instead I must DataMapper
Please correct if I am wrong about any of the statements I have made and Is there anything else that I must know?. Do I need to start reading about JRuby from the scratch or I can go about as usual developing Ruby apps?
I use JRuby everyday.
True:
JRuby has the same syntax
JRuby does not have access to some gems/plugins
I can access Java libraries
Some gems/plugins have jruby-specific versions, some don't work at all. In general, I have found few problems and as the libraries and platforms have matured a lot of the problems have gone away (JRuby has become a lot better).
You can access Java, but in general why would you want to?
False:
JRuby app would take some time to load for the first time, so I have to keep it alive by sending request every 5 mins or so
I cannot use ActiveRecord and instead I must DataMapper
Although I guess it is possible to imagine a server setup where the initial startup/warmup cost of the JVM means you need to ping the server, there is nothing inherent in JRuby that makes this true. If you need to keep the server alive, you should look at your deployment environment. Something similar happens in shared-hosting with passenger where an app can go out of memory after a period of inactivity.
Also, we use ActiveRecord with no problems at all.
afaik, rails 3 is 100% compatible with jruby, so there should be no problem on that path.
like every new platform, you should make yourself comfortable with it by playing around with jruby. i recommend using RVM to do that.
as far as you questions go:
JRuby is just an other runtime like MRI or Rubinus
since JRuby is within the JVM using Java is very easy, but you can also use RJB from MRI
some gems are not compatible, when they use native c libraries, that do not run on JRuby
the JVM and your application container need startup time and some time to load your app, but that is all, there is no need for keep alive, that is wrong
you can use whatever you want, most gems are updated to be compatible with JRuby
#TobyHede mostly covered issues that you thought of you might have so I'll leave it at that.
As for other things to have in mind, it's simply a different interpreter and funny discrepancies will crop up that will take some adaptation.
some methods are implemented differently, such as sleep 10.seconds will throw exception (you have to sleep 10.seconds.to_i) and I remember getting NoMethodError on Symbol class when switching from MRI to JRuby (don't remember which method wasn't implemented), just have in mind slight variations will be there
you will experience hangs and exceptions in gems that otherwise worked for you (pry for example when listing more then one page)
some gems may work differently, pry (again) will exit if you press ctrl+c for example, pretty annoying
slightly slower load times of everything and no zeus
you'll get occasional java exception stack traces with no indication on which line of ruby code it happened
Timeout.timeout often will not work as expected when its wrapped around net code and stars align badly (this has mostly been fixed in jruby core, but it seems to still be an issue with gems that do their own netcode in pure java)
hidden problems with thread-safety in third party code How do you choose gems for a high throughput multithreaded Rails app? - stay away from EventMachine for example
threads will be awesome (due to nativeness and no gil) and fibers will suck (due to no coroutine support in JVM they're ordinary threads), this is why you often won't get a performance boost with celluloid when compared to MRI
you used to run your rails with MRI Ruby as processes in an OS, you knew how to track their PIDs, bloat, run times, kill them, monitor them etc, this part is not evident when you switch to JRuby because everything has turned to threads in a single process. Java world has very good tools to handle these issues, but its something you'll have to learn
killall -9 ruby doesn't do the trick with jruby when your console hangs (which it does more often then before), you have to ps -ef and then track the proper processes without killing your netbeans etc (minor, but annoying)
due to my last point, knowing Java and the JVM will help you get out of tight spots in certain situations (depending on what you intend to do this may be something you actually really need), choice of deployment server will increase or decrease this need (torquebox for example is a bit notorious for this, other deployment options might be simpler, see http://thenerdings.blogspot.com/2012/09/pulling-plug-on-torquebox-and-jruby-for.html)
...
Also, see what jruby team says about differences, https://github.com/jruby/jruby/wiki/DifferencesBetweenMriAndJruby
But yeah, otherwise its "just the same as MRI Ruby" :)