Does anyone know how to identify the issue and fix it?
Many thanks!
The latency does not look like a problem.
The Cloud Debugger API latency metrics will include ListActiveBreakpoint rpcs that deliberately stay open for a long period of time in order to reduce polling frequency. Essentially, the rpc will return when there is a new breakpoint set or when the request times out (at roughly 50 seconds, based on your screenshot).
The Cloud Debugger API requests occur in the background so the latency should not affect your system in any meaningful way.
Related
We are currently using ExoPlayer for one of our applications, which is very similar to the HQ Trivia app, and we use HLS as the streaming protocol.
Due to the nature of the game, we are trying to keep all the viewers of this stream to have the same latency, basically to keep them in sync.
We noticed that with the current backend configuration the latency is somewhere between 6 and 10 seconds. Based on this fact, we assumed that it would be safe to “force” the player to play at a bigger delay (15 seconds, further off the live edge), this way achieving the same (constant) delay across all the devices.
We’re using EXT-X-PROGRAM-DATE-TIME tag to get the server time of the currently playing content and we also have a master clock with the current time (NTP). We’re constantly comparing the 2 clocks to check the current latency. We’re pausing the player until it reaches the desired delay, then we’re resuming the playback.
The problem with this solution is that the latency might get worse (accumulating delay) over time and we don’t have other choice than restarting the playback and redo the steps described above if the delay gets too big (steps over a specified threshold). Before restarting the player we’re also trying to slightly increase the playback speed until it reaches the specified delay.
The exoPlayer instance is setup with a DefaultLoadControl, DefaultRenderersFactory, DefaultTrackSelector and the media source uses a DefaultDataSourceFactory.
The server-side configuration is as follows:
cupertinoChunkDurationTarget: 2000 (default: 10000)
cupertinoMaxChunkCount: 31 (default: 10)
cupertinoPlaylistChunkCount: 15 (default: 3)
My first question would be if this is even achievable with a protocol like HLS? Why is the player drifting away accumulating more and more delay?
Is there a better setup for the exoPlayer instance considering our specific use case?
Is there a better way to achieve a constant playback delay across all the playing devices? How important are the parameters on the server side in trying to achieve such a behaviour?
I would really appreciate any kind of help because I have reached a dead-end. :)
Thanks!
The only sollution for this is provided by:
https://netinsight.net/product/sye/
Their sollution includes frame accurate sync with no drift and stateful ABR. This probably can’t be done with http based protocols hence their sollution is built upon UDP transport.
I'm using jMeter to make load test on a web application. I use also the plugin "jMeter Plugins" to have more Graphs.
My question is
I can't understand the difference between the server hit rate (Server hit per second graph) and the througput (Transactions per Second). The two graphs are very close but they differ a bit in some locations.
I wonder also if "transaction" here means request .. right ??
Thx a lot :)
Both hits per second and throughput are talking about workload, the hits are the request send from the injector over time, meanwhile the throughput is the load that the system is able to handle, both graphs should look the same as long as the application haven't reach its breaking point, after the breaking point the hits will continue increasing triggering a response times increase.
A test in which you note the difference is the peak test (you increase load until you crash the application), when the application exceeds its throughput the 2 plots will diverge.
As you can see the blue curve differ from from the green one after 650RPS, then response times skyrocket and request start failing.
If we let the test continue running, the injector will run out of threads and the hits curve will be the same as the throughput again. Configuring the injectors pool thread.
The area in between the two curves are active request, request that the injector sent and are waiting to be processed.
The hits plot is measured in RPS, it is counting requests not transactions.
The same plot can be generate using the jmeter's composite graph.
server hit rate gives graph of how many hits can server handle per each second for single unit.
Throughput Rate is the amount of transactions produced over time during a test. It’s also expressed as the amount of capacity that a website or application can handle.
http://www.joecolantonio.com/2011/07/05/performance-testing-what-is-throughput/
Using ThreadPoolRuntime, I could get a throughput attiribute that means "The mean number of requests completed per second". It's not what I want. I want to get realtime figure that is not the mean number.
Requests per second is by it's nature an average, so I'm not too sure what you mean by a realtime figure - do you want the number of requests completed in the last second?
The ApplicationRuntimes/[appname]/WorkManagerRuntimes/default/CompletedRequests gives the total number of requests completed for one application, you can use this to calculate an RPS figure over whatever timeframe you want.
Unless this is a custom work manager's thread pool, the number you're going to get back isn't going to be terribly meaningful. And even in the case of a custom thread pool assigned to your particular application component (EJB, WAR file, etc) then the number still isn't likely to mean what you're looking for.
The thread pool is used to perform all work for that component (or in the case of the default thread pool, all work for the server, both internal and client-driven. This means that requests of wildly different 'cost' in terms of CPU and execution time go through the same pool.
What is the problem that you're trying to solve? Is it an understanding of how many requests per second are occurring for particular application components? You might want to look at WLDF as an alternative source for this kind of data, although in either case you'll need to post-process information to get something useful.
Im trying to communicate with 2 xmpp clients but this is not like messaging or chatting. It's more like event caused at one end and action performed at other (realtime). I wish there will not be any latency time when a Client A is trying to send packets to Client B. If available will there be any possible way to minimalize that it should be un noticed.? Is it possible to do this or by any other means?
First of all, that is still messaging.
As for you latency, there will always be some latency when sending data between processes. You haven't said what tolerance levels you are looking for as opposed to what you are getting so it is hard to say what you should do to improve them.
The biggest factors to any current latency you have will be message size and network speed. Of course direct point to point communication would remove one hop for you message, but without knowing your application there is no way of saying whether this is an acceptable direction.
A small message should be delivered in a few milliseconds on a fast network. If it is a slow network, then your problems lie outside of any communications protocol.
We have a memory intensive processing for certain functionality and we would like to limit the number of parallel requests to this processing. We are able to configure by using "Work Managers" in WebLogic and putting a limit on the number of threads for that servlet.
For example, if we put maximim thread limit as 3, then if there are 10 parallel requests; 7 requests are in queue. There could be situations where these the requests waiting in queue could take up to 30-40 minutes to be processed. We did simple testing and the received page cannot be displayed due to timeout after 15 mins and received the message after 1 hour.
Does any one know if there is a setting in WebLogic to increase/decrease timeout and avoid page cannot be displayed?
Appreciate if any one has any thoughts around this.
Does any one know if there is a setting in WebLogic to increase/decrease timeout and avoid page cannot be displayed?
There might be something but I actually didn't check as it would be a bad advice anyway. By looking for this, you are trying to solve the wrong problem here. A browser is just not made for long-running process like the one you are describing (>30mn) even if you don't mind the user waiting (not mentioning that he could refresh the page and queue more and more jobs).
So, the right answer here is in my opinion: use asynchronism, this is the perfect use case. When the user clicks on the button, send a JMS message to a queue (or create a Quartz job) and send the user a page with a request ID telling him to come back later. When the processing is done, update the status somewhere and make the status/result available to the user. Really, the user experience will be better doing this and you'll face less problems than with a browser.
1) Use some other tool (not browser) like WGET where you can control timeout parameter (--timeout).
2) Why do you use HTTP? Use message driven beans and send message JMS to that and don't care about time outs.
Perhaps quartz can do what you need? Start a job and check in on it as you need to?