buffer allocation and minimizing memory allocation

Hello

I am tryint to minimize the buffer allocation and memory in general activity. The code will run 'headless' on a cRIO and our experience and that of the industry as a whole is to ellliminate or minimize any action of distribution and the dynamic memory deallocation.

In our case we treat unfortunately many string manipulations, thus eliminating all the alloc/dealloc memmory is significant (impossible?).

Which leaves me with the strategy of "minimize".

I did some investigation and VI of profiling and play with the structure "on the spot" to see if I can help things.

For example, I have a few places where I me transpoe a few 2D charts. . If I use the tool 'See the buffer allocations' attaced screenshot would indicate that I am not not to use the structure of the preliminary examination International, both for the operation of transposition of the table for the item index operations? As seems counter intuitive to me, I have a few basic missunderstanding either with the "show stamp" tool of the preliminary examination International, or both... The tool shows what a buffer is allocated in the IPE and will once again out of the International preliminary examination, and the 2D table converts has an allowance in and out, even within the IPE causing twice as many allowances as do not use REI.

As for indexing, using REI seems to result in 1.5 times more allowances (not to mention the fact that I have to wire the index numbers individually vs let LabVIEW auto-index of 0 on the no - IPE version).

The example illustrates string conversions (not good from the point of view mem alloc/dealloc because LabVIEW does not determine easily the length of the 'picture' of the chain), but I have other articles of the code who do a lot of the same type of stuff, but keeping digital throughout.

I would be grateful if someone could help me understand why REI seems to increase rather than decrease memory activity.

(PS > the 2D array is used in the 'incoming' orientation by the rest of the code, so build in data table to avoid the conversion does not seem useful either.)

QFang wrote:

-My reasoning (even if it was wrong) was to indicate to the compiler that "I do not have an extra copy of these tables, I'll just subscribe to certain values..." Because a fork in a thread is a fairly simple way to increase the chances of duplications of data, I thought that the function index REI, by nature to eliminate the need to split or fork, the wire of the array (there an in and an exit), I would avoid duplication of work or have a better chance to avoid duplication of work.

It is important to realize that buffer allocations do occur at the level of the nodes, not on the wires. Although it may seem to turn a thread makes a copy of the data, this is not the case. As the fork will result in incrementing a reference count. LabVIEW is copy-on-write - no copy made memory until the data is changed in fact, and even in this case, the copy is performed only if we need to keep the original. If you fork a table to several functions of Board index, there is always only one copy of the table. In addition, the LabVIEW compiler tries to plan operations to avoid copies, so if several branches read from a wire, but only it changes, the compiler tries to schedule the change operation to run after all the readings are made.

QFang wrote:

After looking at several more cases (as I write this post), I can't find any operation using a table that I do in my code that reduces blackheads by including a preliminary International examination... As such, I must STILL understand IPE properly, because my conclusion at the present time, is that haver you 'never' in them for use. Replace a subset of a table? no need to use them (in my code). The indexing of the elements? No problem. .

A preliminary International examination is useful to replace a subset of the table when you're operating on a subset of the original array. You remove the items that you want, make some calculations and then put back them in the same place in the table. If the new table subset comes from somewhere other than the original array, then the POI does not help. If the sides of entry and exit of International preliminary examination log between them, so there no advantage in PEI.

I am attaching a picture of code I wrote recently that uses the IPEs with buffer allocations indicated. You can see that there is only one game of allowances of buffer after the Split 1 table D. I could have worked around this but the way I wrote it seemed easier and the berries are small and is not time-critical code so there is no need of any optimization. These tables is always the same size, it should be able to reuse the same allowance with each iteration of the VI, rather than allocate new arrays.

Another important point: pads can be reused. You might see a dot of distribution on a shift register, but that the shift register must be assigned only once, during the first call to the VI. Every following call to the VI reuses this very spot. Sometimes you do not see an allocation of buffer even if it happens effectively. Resizing a table might require copying the whole table to a new larger location, and even if LabVIEW must allocate more memory for it, you won't always a point of buffer allocation. I think it's because it is technically reassign an existing table instead of allocating a new, but it's always puzzled me a bit. On the subject of the paintings, there are also moments where you see a point to buffer allocation, but all that is allocated is a 'subfield' - a pointer to a specific part of an existing table, not a new copy of the data. For example 1 reverse D table can create a sub-table that points towards the end of the original with a 'stride' array-1, which means that it allows to browse the transom. Same thing with the subset of the table. You can see these subtables turning on context-sensitive help and by placing the cursor on a wire wearing one, as shown in this image.

Unfortunately, it isn't that you can do on the string allocations. Fortunately, I never saw that as a problem, and I've had systems to operate continuously for months who used ropes on limited hardware (Compact FieldPoint controllers) for two recordings on the disk and TCP communication. I recommend you move the string outside critical areas and separate loop operations. For example, I put my TCP communication in a separate loop that also analyses the incoming strings in specific data, which are then sent by the queue (or RT-FIFO) to urgent loops so that these loops only address data of fixed size. Same idea with logging - make all string conversions and way of handling in a separate loop.

Tags: NI Software

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Entered Unwired error cause buffer allocation

Recently, while playing 'Hide the Dots', have I noticed that wiring not not admission of error on the functions (such as the authors of the notifications, queues or nodes of property) may be coming to a bill of costs.

If a cluster of error is X bytes and you have dozens of these unwired (let) laying around, declaring it is buffer allocation [X bytes * notifiers n]? Correct me if I'm wrong, but the old saying no error output?

Edit: I know that is not the wiring error may cause a race condition, the non-LabVIEW-esque program sequence, etc, but I would like to talk about the aspect of memory of this alone.

Hi all

As the 'error' is only a recommended terminal, when he is not wired LabVIEW must locate and assign default values for this entry. To do this, a memory to be allocated. Therefore, not wiring error as well as the terminals not required tickets will actually increase the initial memory allocation. However, this additional allocation should be minimal compared to the rest of your VI.

Why this specific buffer Allocation?

Win Vista, LabVIEW 8.6.1, PXI 8196, LV RT 8.6.1

I have a problem with a PXI program used to control a motor/dynamometer by PID loops on a cycle prescribed thresholds (objectives specific speed/torque to meet).

The normal use of the processor (as the output of the PXI monitor shows) is normally 2%. My loop is 100,000 Hz, and I have been diligent in spreading the bypass, so it runs very efficiently.

A 'normal' test was for 20 minutes, so we have never noticed a problem. However, my client has recently published a test of 8 hours, and he noticed that the CPU would creep upward and upward during the test, to where it was 75% after 8 hours.

I ran my own test of 2 hours and observed the same thing - the CPU usage crept up to 20%.

In the hunt for things, I noticed it is correlated with the size of an array of values of the PXI controller: larger than array, the CPU usage more. During the test, the set values are located above the host right in front of the time, so the table grows slowly as the test goes along.

When the test is finished, the table does not, and nor does the CPU usage. I can go right through to start a new test and the CPU usage drops when I send an order to clear the table. Therefore, I am sure that the size of the array is the problem.

A two hour test contains 120 x 60 x 10 = 72000 set points (the host set points are 10 Hz, 100 Hz setpoints are interpolated from the controller) to 24 bytes, which is 1.728 MB. NOT a RAM huge hit (available from 2 gigabytes).

I couldn't imagine why the existence of this large table would be time-consuming CPU, but the evidence is with myself: the bigger picture, the most used CPU.

In the search for an answer, I started the buffer ALLOCATIONS view and found a place where LV makes a COPY of this buffer, and I don't understand why.

But that would explain things: copy a table from 1.7 MByte to 100 Hz will certainly put a load on the processor.

So here's the code: in the TRANSIENT state table is used to select and interpolate the next set.

When the test is finished, we go to the State of SLOWDOWN, if the table is not yet used:

After that, we are in idle state, where even once, the big Board is not used.

Then, before I have to change the architecture of things to eliminate former set points (I have many problems with accounting), can someone explain WHY the buffer allocation shown is happening?

Note that I show the case of '0', the other is 'default' which manages other 9 out of 10 cases. But there is there again, a buffer allocation when the table is not yet connected to the inside.

More importantly, avoid this allowance?

It's hard to say without poking at him but I saw the similar models result in a copy of the additional buffer.

(1) (less likely) the wire branch off to feed the size of the table is confusing LV and he thinks he needs another copy. I saw this in all LV 7.1 and can not ask with LV 8.6.1.

(2) the sub - VI "to choose and interpolate the next set" has NO control on the connector of the icon on the "root" of the diagram and or data are not connected through. To understand what I'm upgrading to please see the "clear as mud" thread , where it was called Grg McKaskle out of retirement to explain how it can work Subvi in the buffer of the appellant (that's really what you want in the code you showed us).

Reader Digest Version:

When LV 'sees' data be passed to and from a Subvi and there is no operation that will change the content of the data, the data will be passed by reference so sub - VI will do its job in the buffer of appellants.

This image of code shows the difference.

Ben

PS "Buffer Allocation" in the hand catches my attention.

Difference between nio-file manager and nio-memory-manager
Hello
What is the difference between nio-file manager and memory manager Ian? The documentation is not really discuss the differences as far as I know. They all use two nio to store files mapped into memory Don't they? What are the advantages/disadvantages of both?

When to choose the first and when the second during the storage of a large amount of data? Can be used to query data with the filter API? Are there any size limits on both?

Best regards
Jan
Hi Jan,

The difference is that one uses a memory-mapped file and used memory direct nio (as part of the memory allocated by the JVM process) to store data. Both allow data cached out-of-heap storage, which can store more data with a knot of unique cache (FMV) without long GC pauses.
If you use a 32-bit JAVA virtual machine, JVM process will be limited to a total of ~ 3 on Windows and 4 GB on Linux/Solaris. This includes lots and out of the stack of memory allocation.

Regarding the size of the limitations for the Manager of files-Ian, please see the doc the following for more information.
With version 3.5, now is the idea of a Partitioned card support that allows to create more large (up to 8 GB of capacity) for storage of nio. Please refer to the following, doc.

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HTH,
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Does not start, need more and more memory, then crashes. It is SOLVED by deleting DB, panacea.dat, foldertree.json CAUSE global messages: uknown

As a user of Thunderbird long term (currently version 38.2.0 on Win7 x 86 US) today, I caught myself (negatively) by the following problem: at the launch at the start of Thunderbird, the window will appear last closed (and for a short while, I see my files, etc., as left behind, during the last closure of Thunderbird), but then it turns into State "Not responding" (nothing works). When we look in the Task Manager, I see that Thunderbird seizes more and more memory, before this date - after a few seconds - crashing. I really hope that for some help fast, if possible (I desperately need a solution for e-mail job well - ideally the one I had, i.e. Thunderbird with my settings).

What I tried:
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-from Thunderbird in safe mode of Windows (same problem)
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My main question to know how to solve this problem, includes questions such as
? Should I try to delete some files of Thunderbird and try again (which ones?)?
? Can I use a command line "tricks" to get Thunderbird started?
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Thanks for your help!

I think I solved my problem: delete messages from global reach DB and panacea.dat foldertree.json helped - once Thunderbird started again interactively and now I can restore my data files/messages.

Re: Satellite P200d-12U and 4GB memory upgrade

Hello

I was given a Satellite P200-12U with 2 GB of friend of a friend and asked to be upgraded to 4 GB.
Have purchased and installed the memory, but noticed BIOS and still only registered WINDOWs 2GB.
Then went into BIOS

JASAA BIOS V1.40

and I noticed that the options are usually very limited, and that memory is indicated but not selectable.

Do I have reason to think that this machine is limited to 2 GB? And may refer the 4 GB to the shop?

Thanks for any information.

Hello

Can you please send the exact model name?
Subject and then validation you wrote about two different laptop models.

Satellite P200D-12U or Satellite P200-12U?

Satellite L755 - 16L gives the blue screen and physical memory dump

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I bought my L755 - 16L in the month of August.
Until last week it went very well.

Last week I'm going to visit another country he only has the 240V voltage.
Normally at home, I use 100V power supply for my laptop.
After my return when I connect top of laptop and the go blue screen screen work and grant discharge mini information of physical memory.

Usually, I unplug the charger after the judgment.
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If not unplug the charger after stop down and don't use the next day then no problem.
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"The system has rebooted without judgment properly first. "This error can be caused if the system unresponsive, crashed or unexpected power loss.
System

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[Name] Microsoft-Windows-Kernel-Power
[Guid] {331C3B3A-2005-44C2-AC5E-77220C37D6B4}

Event ID 41

Version 2

Level 1

Task 63

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Keywords 0 x 8000000000000002

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[SystemTime] 2011-11 - 27 T 10: 43:19.248036500Z

EventRecordID 48763

Correlation

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[ProcessID] 4
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Computer toshiba-TOSH

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BugcheckParameter1 0xffffffffc0000005
BugcheckParameter2 0xfffff80003717ce5
BugcheckParameter3 0x0
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Hello

In general the BSOD is the product of the problem of hardware or software problem. To check if it of software or hardware associated with deliver its necessary to reinstall the OS and check if the BSOD will appear using the new OS preinstalled.
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I don t think that the different input voltage might affect the functionality of the laptop computer because the laptop uses the universal adapter that supports entry 100V-240V.

BSOD can be caused by faulty memory modules so I think that this test of memory could be useful also

Camileo S10 - Arcsoft doesn't recognize not all files on SD card and internal memory

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Hello nikfam,

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welcome them

How to find the Maxima and Minima for each column of a 2D array?

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I have a 2D chart and I would find the maxima and minima of each column of the 2-D table. Even though I know how to get maxima and minima for the whole picture but don't know how columnwise? Any ideas please?

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Rohit

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dohar9 wrote:

The Sansa Clip + shuffle between songs on the internal memory and external memory SD card?

Yes.

I have 4 GB Clip + with a 8 GB external SD card. What total 12 GB?

In theory, Yes. In actual practice, but it will be probably closer to 10.75 to 11FR.

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N ° the player will play seamlessly two memory slots when you use the random mode.

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Help, please.

Thanks in advance

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blue screen error and the memory of dumping

Dear all,

Beyond 20 days before my knees worked well, with any problem.

OS: win 7 home.

recently I updated all the patches update.that time Windows first problem started in the MSE.

Error: Session "Microsoft Security customer OOBE" stopped because of the following error: 0xC000000D

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Please find the shared memory dump

https://SkyDrive.live.com/#CID=F1D72CACC8DEB263&ID=F1D72CACC8DEB263%21126

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A fatal hardware error occurred.

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Source of the error: Machine Check Exception

Error type: internal Timer error

Processor ID: 4

View details of this entry contains more information.

Hi Er.Nirmal,

You did changes to the computer before the show?

I suggest you try the steps from the following link:

Resolve stop (blue screen) error in Windows 7
http://Windows.Microsoft.com/en-GB/Windows7/resolving-stop-blue-screen-errors-in-Windows-7

Note: Running chkdsk on the drive if bad sectors are found on the disk hard when chkdsk attempts to repair this area if all available on which data can be lost.

Problem opening of files from the two account email, secondary remembered as HDD and USB memory-based external excel...

Problem opening of files from the two account email, secondary remembered as HDD and USB memory-based external excel. Message warning "there was a problem sending the command to the program". I use Windows 7, version studend of microsoft office 2007. This problem does not exist when I use the same USB on the desktop (XP)

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http://support.Microsoft.com/kb/211494

Driver overran the buffer battery and I it keeps restarting my PC every half hour

Hello

I have the problem of driver on stack buffer Ran and me it keeps restarting my PC every half hour as I can't put to win 8.1 caz it crashes or run and antivirus as she hangs with the same thing driver_overran_stack_Buffer.

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Concerning

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To update or, if necessary, uninstall Folder Lock and see if the error resolves.

I might also suggest to update Avast to the latest version.

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Hello

I have OptiPlex SX280 bought 3 years ago

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Given that I need to solve a problem of Supercomputing,

I want to upgrade the processor and the memory instead of replace the computer.

SX280 works with CPU Core2Duo E8200 having the same type of brooch (LGA775)

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The SX280 BIOS is A09.

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Thanks in advance.

Message edited by yongminc on 10/19/2008 21:18

buffer allocation and minimizing memory allocation

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