I know Google Portable Native Client have api to get number of CPU cores
like this :
`long result = sysconf(_SC_NPROCESSORS_ONLN);`
but is there any way to get the total available memory, GPU(type,memory e.t.c)?
or current cpu load?
Thank you
Related
I couldn't find any query command about device being integrated/embedded in cpu or using system ram or its own dedicated gddr memory? I can benchmark mapping/unmapping versus reading/writing to get a conclusion but that device can be under load at that time and behave wrong and it would add complexity to already complex load balancing algorithm that I'm using.
Is there a simple way to check if a gpu is using same memory with cpu so I can choose directly mapping/unmapping instead of reading/writing?
Edit: there is CL_DEVICE_LOCAL_MEM_TYPE
CL_GLOBAL or CL_LOCAL
is this an indication of integratedness?
OpenCL 1.x has the device query CL_DEVICE_HOST_UNIFIED_MEMORY:
Is CL_TRUE if the device and the host have a unified memory subsystem
and is CL_FALSE otherwise.
This query is deprecated as of OpenCL 2.0, but should probably still work on OpenCL 2.x platforms for now. Otherwise, you may be able to produce a heuristic from the result of CL_DEVICE_SVM_CAPABILITIES instead.
It is required of my Haxe program to calculate the average CPU usage of a particular executable/process over a specified period of time.
I understand that the solution is platform specific and would like to achieve it for both Windows and Linux.
The problem is with Memory management because I keep receiving “Out of Memory exception”.
Here are the scenarios where we face the problem:
Please note:
1. The site/application is developed in ASP.Net and uploaded on a server with the following specs:
- Windows Server 2008 (R2) Standard
- Intel Xeon L5520#2.27GHz 2.27GHz
- RAM = 8GB
- System Type = 64bit
The application is event management based web application where the requirements include saving huge amount of data in Sessions etc (mentioning this in case it is relevant)
The applications/site works fine until we:
Edit a file directly on the server
Update a file from repository
Copy/Paste a file (we don’t usually edit code using this technique)
Please note, all of the above hold true ONLY when the traffic to the site is high that is,
The issue/error “Out of Memory” is not produced when the traffic/visits is low
Details of:
System Properties > Advanced > Performance Settings > Advanced tab
Total paging file size for all drives: 16362 MB
In web.config
Is there any way we can debug this problem to the core and find out a solution. Can you please provide links/help where we can further investigate this problem?
Best regards,
Farrukh
Out of Memory Exceptions are common with applications that see periodic transaction surges while keeping larger volumes of data in memory. This problem does, however, depend on your application and architecture. Below are a few pointers:
Hardware - you have Xeon 5500 (Intel Nehalem chips). These are very good at handling memory. You should be good here.
OS - Windows Server 2008 R2 - As an OS this system will handle more than enough memory for you (you are good here, see link for capabilities: Memory Limits for Windows)
Physical Memory - Did you say you have 8 GB on the server? Note you app is allowing 16 GB. There is one issue. If your app requests more memory than physically available you will see your error. But this is not your only concern ...
CLR / GC limitations - Your application has a "paging file size" of 16+ GB. This is probably your issue.
GC is the heart of your problem for you. In terms of why, it is the same reason Java and the JVM have issues whenever an application exceeds 2-4 GB. That requires a look at the actual process of GC.
You have "old generation" and "young generation" Garbage Collection processes. As you app runs the CLR tries to keep your memory space organized. These processes force all threads to pause (phase changes) when GC mark and swap processes occur. The problem here is, depending on how your code is written and the amount of memory you keep around for long periods, you can run into memory issues.
Any time you press a runtime environment to exceed the 4 GB threshold you will see exponential increases in collection times. When you hit the "stop the world" pause (the old gen GC where everything gets cleaned up) the CLR has to go through the entire heap and de-allocate memory. Based on your app, 16 GB may give you issues even with more physical memory (Windows Server 2008 R2 - Enterprise or DataCenter can support 2 TB). Even if you feed it more physical memory you may see LONG collection times when your full GC hits.
Ideally I would do the following:
Get more physical memory (you never want to come withing 600MB of your total physical memory allocated to your application to avoid out of memory errors, but your buffer does depend on your load and the application's ability to handle it ... you may want a larger safety net to be safe).
Once you have the physical memory you need run GC logs while stressing the app. This will give you an idea where you see exponential degradation in performance and what level your app can support when considering Heap size (Memory). You may want to find a way to get your 16GB page down to a smaller size. I do know with .Net 4.0 Microsoft has made some solid improvements to the GC process, including allowing a background thread to maintain GC. This should give you the ability to support larger heaps (in theory) ... but nothing beats real tests on the app. Check out this link for more info:
Garbage Collection Performance (Asp.net 4.0) - Also, as I am limited on links. Navigate to the Fundamentals page for some great explanations on new GC features of ASP.Net 4.0
(http://msdn.microsoft.com/en-us/library/ee787088.aspx#concurrent_garbage_collection)
Hope this helps!
PS - Anyone out there on lesser hardware will need to be aware of the ASP.NET use of the GC thread. If you are running something in development like a Core Duo you have to consider that 50% of your compute power will go to GC optimization. This means that Hardware (number of cores) is important to consider. If you have more than you need this process should theoretically help performance. If you are constrained on cores either get better hardware or use an older version of ASP.Net or consider turning the feature off (if possible). Second, if latency is a concern, using "hyper-threading" does have an impact on performance as well. You always get better performance on "physical" cores ... but that will not be a concern for 99.9% of the applications out there.
2 GB by default. If the application is large address space aware (linked with /LARGEADDRESSAWARE), it gets 4 GB (see http://msdn.microsoft.com/en-us/library/aa366778.aspx)
They're still limited to 2 GB since many application depends on the top bit of pointers to be zero.
My Asp.net application uses
25-30% of the CPU on a test server which has 600 MB Ram on it.
I can see the asp_wb process taking that much percentage of CPU.
This is when I am testing using one user.
How many users can the server afford then without falling over?
Is there a relationship between the CPU Usage and number of user aka if there are 2 users my application will sky rocket to 60% of memory usage?
Or does/Should/How does the server handle this?
The asp.net is base on pools and not on users.
Some memory per user is going on user session, but I believe that you not hold huge amount of data on sessions (did you ?).
Now I suggest ti run process explorer from sysinternals, and check on w3wp.exe the working set and the virtual size of the memory for this. You can do that by open this 2 columns on Process Memory tab.
Then you see there how many memory asp.net needs for your application.
Second step if to check how you have configure your pool by open it. Maybe you have configure it to recycle too often, or to recycle when you have more than 125k working set memory, and your program have 200k working set memory. So you need to recalibrate some values.
Together with process explorer you can see how much memory your application need, and setup correctly the pool.
Of cource maybe there are other problems and other issues with the memory but asp.net is not eat memory for every user and you need to check where your memory is used - and the process explorer is a good tool for this job.
Hope this help.
I'm looking for a way for the application itself to monitor the amount of memory it is using, so I can record it in a log file every hour or so and keep an eye on the applications usage.
Its all hosted so we can make changes to the system to see what is going on so the solution will have to be from within the application code.
We may in future use the memory information to affect the caching policies.
Hmm, how detailed information do you need? If you just want the memory usage you can ask the GC. It knows. ;)
long bytes = GC.GetTotalMemory(false); // use 'false' to not wait for next collect
The variable 'bytes' will contain the number of bytes currently allocated in managed memory. I'm not sure whether the managed memory entails the entire process or just the AppDomain. You'll have to test this by running several AppDomains in one process and see if managed memory allocation is measured cross AppDomains. If they don't, then you can use this to measure total memory usage in an ASP.NET application.
If you want more specific information there's a diagnostics API for the CLR which you could interface with. There's also plenty of memory profilers out there, but if they'll work within an ASP.NET application I cannot say.
As an alternative, if you want more detailed information, you can read the performance counters using the System.Diagnostics.PerformanceCounter class. Here are some of the counters that you can plug into:
Request Bytes Out Total
Request Bytes In Total
Request Wait Time
Requests Executing
Requests/Sec
Errors Total