I am doing calculations in milliseconds and I really do not want my thread to spend more time doing time calculations rather the job it is assigned to do. However I want to implement something that:
1- It should not generate more than n requests per second
2- If it has generated less, it should start at zero for the next second(obviously :D)
I am trying to do some performance benchmarking where my goal is to give all cpu to only processing and not time computations after every request. Roughly, I am processing
08:36 - 171299
08:37 - 170970
08:38 - 163763
I want to make sure I do not make more than 160000 requests per minute here. How to acheive that is the problem.
Thanks in advance!
You can combine ScheduledExecutorService to run some code every second and this answer to set timeout on that code. In the end, your runnable that should have 1-second timeout should generate up to n requests, and if it times out, it will start in next second with new context.
Related
I am testing a certain "functionality" that happens after log in.
The test case is 500 users exercising that functionality within 5 minutes.
I can add a synchronising timer after the log in, to ensure all 500 threads have logged in but then it will do all 500 "functionality" tasks at once, rather than 5 minutes, which will crash the app (it thinks there's a DDoS attack and shuts down).
Right now, I am handling this by giving some think time after login, to slow down login to a stable figure that I can predict and then start "functionality" at each thread's turn, as scheduled by: the main scheduler + the the log in response time + the think time...
But that's a bit fuzzy.
Is there a way to "ramp up" tasks once already running?
I can think in two options.
The first one is two use random times. You would use the range from 0 seconds to 300 - 1 that is [0-300) or using millis [0-300000). Then sleep the thread basesd on this ramdon time.
This approach can be a little more realist, because for instance, in a specific second of the given interval you don't have any threads starting and in other particular second you have 2-3. This still should be well balanced in general, since you won't make all petitions at start.
The second one is to start the threads uniformly. During your configuration time (login and before firing the threads) you can use something like an AtomicInteger, initializing it with new AtomicInteger(0) and calling getAndIncrement() to assign the possition of the thread, in the range [0-500) and then when you fire the threads sleep 300.0 * id / 500.0 milliseconds to execute the task/petition.
By default JMeter executes requests as fast as it can, you can "throttle" the execution to desired throughput (request per minute) rate using Constant Throughput Timer.
Example Test Plan would look like:
Thread Group
Login
Synchronizing Timer
Functionality
Constant Throughput Timer
Constant Throughput Timer follows JMeter Scoping Rules so you can apply it either to single sampler or to a group of samplers.
I need to run a performance test on JMeter against a SOAP-based webservice. I have set up the Tests for this. What I want to do is make 5 requests one after another in 1 thread group with a delay of 1 second between the requests for a certain amount of time (ex. 2 hours ...) BUT I don't want to wait for the response of one request and then proceed to the next i.e. I want to fire 1 request, wait exact 1 second, fire the second, wait exact 1 second fire the next request etc. and then collect the results after the test has finished. This is a requirement.
My Questions:
1. Does JMeter have any option to accomplish this task?
2. If the answer to the 1st question is yes, how would I accomplish such a task?
3. If the answer to the 1st question is no, is there a substitute for JMeter that can handle such a task?
Thanks,
You can add a Timer element to your samplers. You can configure the Timer to be constant (1 sec) or even choose the wait time to be drawn from a Normal distribution. Find out more info here: http://2min2code.com/articles/jmeter_intro/constant_timer
For the moment there is no possibility to configure JMeter to send requests as you described.
However JMeter provides the option to limit JMeter's throughput to 1 request per second. See How to use JMeter's Throughput Constant Timer for details on how to get this done.
I want to simulate CPU bound jobs in my simulator and i need a calculation or code that run for 1 second in the cpu ...how i will do it...
i am using the folllowing code
long Time1 = System.currentTimeMillis();
///calculation or loop that spends 1 second in cpu
long Time2 = System.currentTimeMillis();
System.out.println(Time2-Time1);
Now i need the calculation that take 1 second...I also need to simulate for 2 ,3 to 4 seconds
what code i should put in line 2.?
If you really meant binding a job to the CPU for 1 second, I don't think it is possible only with pure Java. The reason is that the OS will still remove the process from the CPU, schedule it again and so on for a number of times within 1 second. So you need to make a special kind of request to the OS to do this. The request should go and affect the process scheduling algorithm of the OS. But this is not how we want our applications to consume the CPU. We want the CPU to honor the interrupts and so on. So may be your intension is not clearly mentioned in the question or you might be trying to test something special and uncommon.
If you are just simulating something, may be you might just use a sleep() call as suggested in the comments which actually would not be consuming the CPU for 1 second but allows you to assume so for the simulation purpose.
I want to do the following. I count the occurence of an event in my program. What I wish to achieve is that at the end of every hour (Of the MST i.e the time zone where I am in) the count be recorded in the database for that hour. All I need is a code snippet which would execute at the end of every hour. Note that I don't want the thread to sleep because I also need to update counts when events occur.
You can implement a TimerTask so search for that. Or if you can use Quartz. Google search should be your first stop.
In Java, there's no way to ensure that a Runnable gets executed exactly at a given time.
You can only schedule a Runnable to be executed at intervals of approximately a given time. If that's enough for you, then a java.util.Timer or Executors.newSingleThreadScheduledExecutor() is good enough. You only need to put your counter in a thread-safe and atomic variable (AtomicInteger may be enough, depending on the numbers you are expecting to have).
If you want to have extreme precision, then you'd better modify your event handler, so that, before recording the event, it checks in which hour it is and, depending on that, it uses a different "slot" inside a queue. Finally, your scheduled task would gather old queue slots, removing them from the queue and storing to database. (I think this is excessive, but it's up to you).
I have an application that checks a resource on the internet for new mails. If there is are new mails it does some processing on them. This means that depending on the amount of mails it might take just a few seconds to hours of processing.
Now the object/program that does the processing is already a singleton. So right now I already took care of there really only being 1 instance that's handling the checking and processing.
However I only have it running once now and I'd like to have it continuously running, checking for new mails more or less every 10 minutes or so to handle them in a timely manner.
I understand I can take care of this with Timer/Timertask or even better I found a resource here: http://www.ibm.com/developerworks/java/library/j-schedule/index.html that uses Scheduler/SchedulerTask. But what I am afraid of.. is if I set it to run every 10 minutes and a previous session is already processing data it will put the new task in a stack waiting to be executed once the previous one is done. So what I'm afraid of is for instance the first run running for 5 hours and then, because it was busy all the time, after that it will launch 5*6-1=29 runs immediately after each other checking for mails and/do some processing without giving the server a break.
Does anyone know how I can solve this?
P.S. the way I have my application set up right now is I'm using a Java Servlet on my tomcat server that's launched upon server start where it creates a Singleton instance of my main program, then calls some method to do the fetching/processing. And what I want is to repeat that fetching/processing every "x" amount of time (10 minutes or so), making sure that really only 1 instance is doing this and that really after each run 10 minutes or so are given to rest.
Actually, Timer + TimerTask can deal with this pretty cleanly. If you schedule something with Timer.scheduleAtFixedRate() You will notice that the docs say that it will attempt to "make up" late events to maintain the long-term period of execution. However, this can be overcome by using TimerTask.scheduledExecutionTime(). The example therein lets you figure out if the task is too tardy to run, and you can just return instead of doing anything. This will, in effect, "clear the queue" of TimerTask.
Of note: TimerTask uses a single thread to execute, so it won't spawn two copies of your task side-by-side.
On the side note part, you don't have to process all 10k emails in the queue in a single run. I would suggest processing for a fixed amount of time using TimerTask.scheduledExecutionTime() to figure out how long you have, then returning. That keeps your process more limber, cleans up the stack between runs, and if you are doing aggregates, ensures that you don't have to rebuild too much data if, for example, the server is restarted in the middle of the task. But this recommendation is based on generalities, since I don't know what you're doing in the task :)