I would like to measure the upload and download speed of data in iPhone, is any API available to achieve the same? Is it correct to measure it on the basis of dividing total bytes received with time taken in response?
Yes, it is correct to measure the total bytes / time taken, that is exactly what the speed is. You might want to take an average if you want to constantly show the download speed.., like using 500 bytes and the time it took to download those particular ones.
For doing this you could like have an NSMutableArray, as a buffer, which you empty idk every 2 seconds. Then you do [bufferMutableArray length]/2 and you know how many bytes a second you had those 2 seconds. When you empty the buffer ofc append to the data you are downloading.
There is no direct API to know the speed.
Total data received/sent and time only will give you average speed. There use to be lot of variation in the speed over the time so if you want more accurate value then do the speed calculation based on sampling.
(Data transferred in 1 miniut) /(60 seconds) ---> this solution only if you need greater accuracy in the speed calculation. The sampling duration can changed based on the level of accuracy required.
Related
When the query contains a reference to only data from stream buffer, the query returns the results correctly but doesn't show any bytes billed, any links that explain this behavior/ confirm would be helpful
Last year, we've been confirmed that Data accumulated in the streaming buffer is not calculated towards "bytes processed" and therefore not billed.
It's unknown if the BigQuery team will change this, but since data usually doesn't stay in the buffer for long (typically less than 90 minutes, and much less if you stream at high rate), then maybe this behavior will stay this way for some time.
Just keep in mind that once data is moved to the permanent storage, all subsequent queries reading that data will report bytes processed and bill accordingly.
I am using sumo for traffic signal control, and want to optimize the phase to reduce some objectives. During the process, I use the traci module as an output of states in traffic junction. The confusing part is traci.lane.getWaitingTime.
I don't know how the waiting time is calculated and also after I use two detectors as an output to observe, I think it is too large.
Can someone explain how the waiting time is calculated in SUMO?
The waiting time essentially counts the number of seconds a vehicle has a speed of less than 0.1 m/s. In the case of traci.lane this means it is the number of (nearly) standing vehicles multiplied with the time step length (since traci.lane returns the values for the last step).
Using INFO CPU command on Redis, I get the following values back (among other values):
used_cpu_sys:688.80
used_cpu_user:622.75
Based on my understanding, the value indicates the CPU time (expressed in seconds) accumulated since the launch of the Redis instance, as reported by the getrusage() call (source).
What I need to do is calculate the % CPU utilization based on these values. I looked extensively for an approach to do so but unfortunately couldn't find a way.
So my questions are:
Can we actually calculate the % CPU utilization based on these 2 values? If the answer is yes, then I would appreciate some pointers in that direction.
Do we need some extra data points for this calculation? If the answer is yes, I would appreciate if someone can tell me what those data points would be.
P.S. If this question should belong to Server Fault, please let me know and I will post it there (I wasn't 100% sure if it belongs here or there).
You need to read the value twice, calculate the delta, and divide by the time elapsed between the two reads. That should give you the cpu usage in % for that duration.
I am trying to fetch the total number of successful logins using Graphite's render API.
http://localhost/render?target=hitcount(stats_counts.login.success,"99years",true)&from=-99years&format=json
This query is taking too long to execute (~ 30 seconds).
Is this the correct way to fetch the total number ?
Depends on-
The amount of data that the API call has to go through to render this query.
Granularity- One point per month will be ~30 times faster than a point a day.
Physical host specs- While you query use iostat -x 1 to see if your disk is doing 100% IO.
In http://code.google.com/intl/es-ES/appengine/docs/quotas.html#Channel you
can read that with billing enabled the maximum channel created rate is 60
creations/minute. Does it mean that we can created only 86,400
channels/day. It's very low rate, isn't it? And if i have estimated that I
could have peaks of for example: 4,000 creations/minute... What i can do?
60 creations/minute are few creations if the channels are 1to1... Is this
correct?
My interpretation of that section is that you will NOT be able to create 4k connections per minute. Here is how I would think about it: over ANY 1-minute period, no more than 60 channels can be created. For example, you can create 60 channels at time T. Then, for the next 60 seconds you won't be able to create any. Or, you can create 30 at time T. Then, every 2 seconds, create a channel.
I believe another way to think about this is in terms of the token bucket algorithm.
Anyway, I believe you can fill out this form to request a higher limit. There is a link to that form from the docs that you linked to in your question.