Commit Charge

[deepakumar]

Hey friends,

Hello friends & guests this post aim at sharing information about "Commit charge" some of us must be aware of this term & many don't know what the Hell is this, so here is this article that will help you to understand another aspect of your wonderful Windows...

[FONT=&quot]In computing, commit charge is a term used in Microsoft Windows operating systems to describe the total amount of virtual address space for which the backing store is the pagefile. It may be thought of as the maximum potential pagefile usage.[/FONT]
[FONT=&quot]Overview
The Windows Task Manager utility, in its Performance tab, shows three counters related to commit charge:
• Total is the amount of pagefile-backed virtual address space in use, i.e., the current commit charge. The corresponding performance counter is called "Committed Bytes".

• Limit is the maximum possible value for Total; it is the sum of the current pagefile size plus the physical memory available for paging (this excludes RAM that is assigned to non-pageable areas). The corresponding performance counter is called "Commit Limit".

• Peak is the highest amount that the total commit charge has reached since the computer was last rebooted.[/FONT]

[FONT=&quot]The program Process Explorer reports the same set of values with the slight variation that Total is called Current there and additionally provides percentages of Peak and Current towards the Limit value.
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[FONT=&quot]The commit charge increases when any program is opened and used, and goes down when a program is closed. It will also change when already-running programs allocate or free private virtual memory; for example, with the VirtualAlloc and VirtualFree APIs.
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[FONT=&quot]In the Task Manager utility under Windows XP and Windows Server 2003, the graphical displays labeled "PF usage" and "Page File Usage History" actually reflect not the pagefile contents but the total (or current) commit charge. The height of the graph area corresponds to the commit limit. Despite the label, these do not show how much has actually been written to the pagefile, but only the maximum potential pagefile usage at the moment. In Windows 2000 and Windows NT 4.0, these same displays are labeled "Mem usage" but again actually show the commit charge.
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[FONT=&quot]In Task Manager's "Processes" display, each process's contribution to the "total commit charge" is shown in the "VM size" column. The total commit charge will always be larger than the sum of these values, as the total includes system-wide allocations such as the paged pool.
The "Mem Usage" column in Task Manager's "Processes" display shows each process's current working set. This is a count of physical memory (RAM) rather than virtual address space. It represents the subset of the process's virtual address space that is valid, meaning that it can be referenced without incurring a page fault.
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[FONT=&quot]The commit charge for each process does not include other major contributions to the process's virtual address space, such as mapped files. For this reason, the process's working set may be larger than its "VM size" (its contribution to "total commit charge"), and the total commit charge is not at all inclusive of the total memory (physical plus virtual) actually in use.
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[FONT=&quot]The commit limit may be increased by either creating additional pagefiles or, if pagefile expansion is enabled, by expanding an existing one. The operating system will expand the pagefile automatically, if possible, when the total commit charge approaches the limit. In such an event a popup window will be displayed stating that "The system is running low on virtual memory."
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[FONT=&quot]If the system ever runs completely out of commit charge (that is, if the total reaches the limit), a popup window will be displayed stating that "The system is out of virtual memory," and it may become extremely sluggish or even nonresponsive. Closing programs (if the user is still able to do so at this point) decreases the total commit charge and may thereby free up the system.

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Hope this article helped you to get some idea about "Commit charge" it might sound a little technical, trust me i tried to be as simple as possible.
Please do write in your suggestions,feedback,advice...much appreciated...

 

[Bill2]

Deepak, I dont want to be rude and at least you've taken the trouble, but that kind of info (in formal, jargonized language) is available all over the internet. IMHO, you'll be doing the SF comunity much better service if you distill the concepts into simple language that even my granny can understand. As it is right now, noobies will have trouble grasping it and oldies already know it all. Again, no offense meant and think about it.

 

[youllbelost]

Good to know!!..(Did wikipedia for bettter understanding)

 

[deepakumar]

Deepak, I dont want to be rude and at least you've taken the trouble, but that kind of info (in formal, jargonized language) is available all over the internet. IMHO, you'll be doing the SF comunity much better service if you distill the concepts into simple language that even my granny can understand. As it is right now, noobies will have trouble grasping it and oldies already know it all. Again, no offense meant and think about it.

Bill i know while writing this article i kept on thinking will a layman be able to understand it...i agree with you on it but i couldn't make it much simpler but i promise will sit down again after 4 days (going on a vacation) & will edit the technical parts & remove all the jargon...i'm not offended as i already mentioned that i was expecting such feedback & all are heartily welcome bcz that's how i can improve...this was something i had learn a long time ago...Thnx again Bill....

 

[KronKyrios]

I just happened to finish writing up something for my friends which directly addresses Bill's concerns. Here is what I hope is an explanation of Commit Charge which anyone can read.

And if you want the really short and sweet version, just look at the pic that matches your system and read the single line above it. That is all you really need to know when someone asks you about your commit charge.

Here's what I wrote:

Commit Charge
I saw some people comparing their memory usages for Windows 7 in a forum. And of course there was had the one guy boasting a 440 MB memory usage with Firefox open. Actually, he was reporting what Windows makes obvious on the Performance tab of the Task Manager. That is, the Physical Memory Usage - The number under the Green Vertical Bar labeled "Memory". (Center-Left in the Window).

The thing is, to get an accurate count of how much memory Windows is using (your "Commit Charge"), you take the number below the Green Bar labeled "Memory", and add it to the "Cached" number in the stats in the (directly below that bar in the section titled "Physical Memory (MB)" to find out how much memory is actually being used by Windows. The Cached Memory is the amount of RAM that has already been loaded to the physical RAM, and then swapped to Disk because it is not being used often. Other terms for the Cached Memory are "Virtual RAM", and "SwapFile"

For Vista and Windows 7, you look at the "Memory" and add it to the "Cached"


Windows can appear to be working Voodoo behind the scenes to determine what goes into the swapfile and what stays in your faster Physical RAM. In this guy's case, he had a 330 MB Cache which, with his 440 MB (Physical) "Memory" usage puts him at around 770 MB used (that's not his screenshot up there). That's still really good for Windows 7. But when he shut down Firefox, it was still 770 MB. He noticed a 40 MB drop on his Physical RAM, but his Virtual RAM increased by 40 MB when he closed it.

What Deepak said about Windows not necessarily using all the RAM it has set aside in it's pagefile is true. Windows might not actually be using all the space in the Cache file it has set aside for a swapfile. To check this would be a more technical process, and Deepak certainly has the knowledge to describe how this is done if anyone is interested. I'm not quite sure myself, but just knowing how to calculate your Commit Charge is good enough for most people.

By the way, XP's Task Manager reports this differently, and you would have to do the math to see your physical RAM, whereas your "Commit Charge" is in the status bar no matter what tab you are looking at. Coincidentally, the spot where we find the "Physical Memory in Seven, we see the commit charge number on XP. The green bar in XP is labeled "PF Usage". PF Stands for PageFile, which has essentially the same meaning as "Commit Charge". Why didn't Microsoft just improve the section for Physical RAM and leave the Commit Charge there as the primary indicator of usage when they rolled out Vista? My guess is that it's more of Microsoft's Voodoo.

For XP, you look at the first number after "Commit Charge"


by Kron Kyrios on 2011-06-02

P.S. A few of notes.

I know this is a Windows 7 Forum, but I include a Windows XP example. As I stated, I wrote this for friends. Then I decided to leave that info in because the information is relevant to anyone needing to know how Windows 7 differs from XP.

In both screenshots, the systems are in quite good shape. In the Windows 7 example, around 1000 MB is about the minimum you can expect to see on a clean system just loaded to the desktop. Also, the number of processes is 31 (on the right, under System) is also a low number. In the XP example, 910 MB is huge if there were no applications open, but there were 10 applications running at the time, including a couple of memory hogs. Normally, on just loading to the desktop in XP, the number of processes I have is 21 with no applications running and it shows 34 here (some applications count more than one process).

Also here's a quick tip: If you press CTRL-SHIFT-Esc you go straight to the Task Manager in Windows 7 (or Windows XP).

 

[Bill2]

Good job.