What data point this graph is using? Is the graph representing TTFB (time to first byte) or TTLB (time to last byte)
Here are the settings:
Graph is representing TTLB (time to last byte) because it uses JMeter's Response time
If you want TTFB (time to first byte), you need to use Latency
JMeter measures the latency from just before sending the request to just after the first response has been received. Thus the time includes all the processing needed to assemble the request as well as assembling the first part of the response, which in general will be longer than one byte
If you want to display TTFB, a trick could be to replace latency with response time columns values and then display values in graph
In JMeter :
response time is Time To Last Byte (TTLB)
latency is Time To First Byte (TTFB)
See:
https://jmeter.apache.org/usermanual/glossary.html
Related
In a thread i am passing 5 sample is there any way to get the total response time of starting and ending sample. Need to calculate the time from starting api time as start time and ending time of last response among the 5
Put all the requests under the Transaction Controller, it calculates cumulative time for all its children execution.
More information: What is JMeter’s Transaction Controller?
I'm executing performance testing using JMeter and Blazemeter report, but the response time value is the same as latency time value.
can somebody explain?
I attach the graph results:
Latency Time Graph
Response Time Graph
It just means that the response is small/empty. The values are TTLB and TTFB, See explanantion about the difference
Latency is a difference between time when request was sent and time when response has started to be received.
Response time (= Sample time = Load time = Elapsed time) is a difference between time when request was sent and time when response has been fully received.
So Response time always >= latency.
The larger file is, the larger difference between response time and latency will be.
I ran a JMeter test for 193 samples
where I could see my average response time as 5915ms and Throghput as 1.19832.
I just want to know how are they exactly related
All the answers are in JMeter Glossary
Elapsed time. JMeter measures the elapsed time from just before sending the request to just after the last response has been received.
Throughput is calculated as requests/unit of time. The time is calculated from the start of the first sample to the end of the last sample. This includes any intervals between samples, as it is supposed to represent the load on the server.
The formula is: Throughput = (number of requests) / (total time).
The relationship is: higher response time - lower throughput and vice versa.
You can use charts like Transactions per Second for throughput and Response Times Over Time for response times to get them plotted on your test timeline and Composite Graph to put them together. This way you will be able to track the trends.
All 3 charts can be installed using JMeter Plugins Manager
TL;DR
No, but yes.
Both aren't related directly, but when increasing Throughput, it will probably affect server response time due to load/stress on server.
If there are timeout errors response time will probably increase.
But for validation or firewall errors - response time will probably decrease.
There's a long explanation in JMeter archive, last is using Disney to demonstrate:
Think of your last trip to disney or your favorite amusement park. Lets define capacity of the ride to be the number of people that can sit on the ride per turn (think roller coaster). Throughput will be the number of people that exit the ride per unit of time. Lets define service time the the amount of time you get to sit on the ride. Lets define response time or latency to be your time queuing for the ride (dead time) plus service time.
In terms of load/Performance testing. Throughput and Response times are inversely proportional. i.e
With increase in response time throughput should decrease.
With increase in Throughput response time should decrease.
You can get more detailed definitions in this blog:
https://nirajrules.wordpress.com/2009/09/17/measuring-performance-response-vs-latency-vs-throughput-vs-load-vs-scalability-vs-stress-vs-robustness/
Throughout increases to some extent and remains stable when all the resources becomes busy. Now, if user requests increases further at this point response time would increase. But if response time increase is only because of internal queuing then due to the fact that system is taking more requests in at the same time response time is also increasing, throughout doesn't change. When queues are full more requests should fail. If response increase is due to some delay in processing or serving the request, for example running a query on database then due to the fact that system is not accepting more request and at the same time response time is also increasing, consequently throughout would drop.
Just a general explaination.
Respose Time : It is the time calculated when user send the request till request gets finnished.
Throughput : It is server property that number of transaction or request can be made during certain amount of time. here 1.19832 /minute means server cand hadle 1.19832 sample per minute.
As Respose Time increses Throughput increases.
I received an requirement were I need to display the response time, number of threads running, latency and throughput in one report. I used below code in Beanshell post processor to display throughput, response time and number of threads:
long repons=prev.getTime();
vars.put("responseTime",String.valueOf(recons));
//print("res" +responseTime);
log.info("Response time" + repons);
long thread=prev.getAllThreads();
vars.put("threads", Integer.toString(prev.getAllThreads()));
log.info("Thread number is"+thread);
float throughput=thread/repons;
log.info("Through put"+throughput);
I guess it is wrong. Can anyone help on this?
You have syntax error in your script, you have repons in the first line and recons in the second, they should be the same
It is better to use JSR223 Elements and Groovy language for scripting.
And finally, your approach is wrong, according to JMeter glossary:
Throughput is calculated as requests/unit of time. The time is calculated from the start of the first sample to the end of the last sample. This includes any intervals between samples, as it is supposed to represent the load on the server.
The formula is: Throughput = (number of requests) / (total time).
So you need to divide total number of requests by total time taken to
execute these requests, your "code" most likely will be returning zero throughput
You can consider the following workarounds:
Use Backend Listener and a 3rd-party visualisation tool, see Real-time results article for details.
Run your JMeter test via Taurus framework which has Interactive Reporting feature
How is this possible that in Jmetetr increasing number of users (threads) in my test did not changed the latency (Response time)?
I got the same latency for 100 threads and for 300 threads.
Latency is the difference between the time when a request was sent and time when the response has started to be received.
As per JMeter Glossary
JMeter measures the latency from just before sending the
request to just after the first response has been received. Thus the
time includes all the processing needed to assemble the request as
well as assembling the first part of the response, which in general
will be longer than one byte. Protocol analysers (such as Wireshark)
measure the time when bytes are actually sent/received over the
interface. The JMeter time should be closer to that which is
experienced by a browser or other application client.
Response time (= Sample time = Load time = Elapsed time) is a difference between the time when the request was sent and time when the response has been fully received.
As per JMeter Glossary
JMeter measures the elapsed time from just before sending the request
to just after the last response has been received. JMeter does not
include the time needed to render the response, nor does JMeter
process any client code, for example, Javascript.
So Response time always >= latency.
So it is possible that you may have same Latency for 100 and 300 threads but Response time will be different or increased.
If you have stable network connectivity between JMeter and Application Under Test it is expected that Latency wouldn't change not matter how many threads you kick off. It is "pure" network metric which tells how long did it take for the request to reach to the server.
Check out How to Analyze the Results of a Load Test article to see the impact of Latency for the end user