{"id":50673,"date":"2010-04-12T00:01:00","date_gmt":"2010-04-12T00:01:00","guid":{"rendered":"https:\/\/blogs.technet.microsoft.com\/heyscriptingguy\/2010\/04\/12\/hey-scripting-guy-can-i-use-windows-powershell-to-lower-the-priority-of-a-process\/"},"modified":"2010-04-12T00:01:00","modified_gmt":"2010-04-12T00:01:00","slug":"hey-scripting-guy-can-i-use-windows-powershell-to-lower-the-priority-of-a-process","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/scripting\/hey-scripting-guy-can-i-use-windows-powershell-to-lower-the-priority-of-a-process\/","title":{"rendered":"Hey, Scripting Guy! Can I Use Windows PowerShell to Lower the Priority of a Process?"},"content":{"rendered":"

\"Bookmark<\/a> <\/p>\n

 <\/p>\n

\"Hey,<\/p>\n

Hey, Scripting Guy! I have a problem with a rather annoying program at work. The program starts up and runs with high priority. When it does this, my computer is slow as a snail, and as unresponsive as a bear hibernating in the winter. I would like to use Windows PowerShell to lower the priority of this process. Can this be done?<\/p>\n

— CS<\/p>\n

\n

 <\/p>\n<\/p>\n

\"Hey,Hello CS, Microsoft Scripting Guy Ed Wilson here. Speaking of winter, the Scripting Wife and I are heading to Raleigh, North Carolina<\/font><\/a>, this weekend to visit some friends, and to see an ice show. It should be pretty cool. (As an aside, I have visited nearly one-quarter of all the countries in the world, but this will be my first visit to the capital city of my home state. So I am psyched.) <\/p>\n

CS, you mention bears. One thing to keep in mind about hibernating bears in the winter is that not all bears actually hibernate. Polar bears do a sort of waking hibernation<\/font><\/a> that allows them to conserve food, but I imagine if you came across one, he would be rather responsive. Just a safety tip as it were—it might be somewhat interesting if one were to awaken a 1,500-pound (680-kilogram) bear that was snoozing because he was hungry. My favorite polar bear is named Knut<\/font><\/a>, and the Scripting Wife and I had the opportunity to meet him in Berlin, Germany<\/font><\/a>, when I was there teaching a Windows PowerShell class. We went to the Berlin Zoological Garden<\/font><\/a> and spent a lovely day taking pictures and walking around. As you can see from this photo I took, Knut is no longer a little cub, but he is still cute. <\/p>\n

\"Photo<\/p>\n

\n

 <\/p>\n<\/p>\n

CS, you can use Windows Management Instrumentation (WMI) to work with the priority of a process in Windows PowerShell. To see the priority of a process (such as Notepad) use the Get-WmiObject<\/b> cmdlet to query the Win32_Process<\/b> class. You could use this command (or using the gwmi<\/b> alias and positional arguments, it would be gwmi Win32_process<\/b>), but you would get back several pages of information about every process on your computer:<\/p>\n

Get-WmiObject -Class win32_process<\/p>\n

<\/font><\/span><\/p>\n

To limit the information that is returned to only the Notepad process, you can add a filter to your command (gwmi win32_process -f “name=’notepad.exe'”<\/b> using the alias, positional arguments, and partial parameter completion):<\/p>\n

Get-WmiObject win32_process -Filter “name=’notepad.exe'”<\/p>\n

<\/font><\/span><\/p>\n

Using only the filter to limit results to the Notepad process may be just ducky for you. Depending on how busy I am, I may simply search through the 60 lines of output and find the priority<\/b> property to see at what priority the process is currently running. This is shown in the following image.<\/p>\n

\"Image<\/p>\n

<\/p>\n

If I have more time, I may pipe the results to the Format-Table<\/b> cmdlet and choose the properties I am interested in examining. This is illustrated here:<\/p>\n

PS C:> gwmi win32_process -f “name=’notepad.exe'” | Format-Table name, priority, Handle -AutoSize<\/p>\n

<\/font><\/span><\/p>\n

<\/p>\n

 <\/font><\/p>\n

<\/span><\/p>\n

name        <\/span>priority Handle<\/p>\n

<\/font><\/span><\/p>\n

—-        <\/span>——– ——<\/p>\n

<\/font><\/span><\/p>\n

notepad.exe        <\/span>6 4236<\/p>\n

<\/font><\/span><\/p>\n

<\/p>\n

 <\/font><\/p>\n

<\/span><\/p>\n

<\/p>\n

 <\/font><\/p>\n

<\/span><\/p>\n

PS C:> <\/p>\n

<\/font><\/span><\/p>\n

At any rate, MSDN documentation<\/font><\/a> tells us that the priority<\/b> property of the Win32_Process<\/b> WMI class is reported as a range of numbers\n from 0 (lowest) to 31 (highest). <\/p>\n

To set the priority of a process, use the SetPriority<\/font><\/a> method. The thing that is confusing is that the SetPriority<\/b> method takes an integer to tell it which priority to set; however, it is a different number than the one that you retrieve from the priority<\/b> property. To use this method, you need to refer to the table on MSDN<\/font><\/a> that details the allowed values and their meanings. Table 1 is a summary of those values. <\/p>\n

Table 1  <\/span>Values and Meanings of the SetPriority Method<\/p>\n

<\/strong><\/p>\n\n\n\n\n\n\n\n\n\n
\n

Value <\/p>\n

<\/strong><\/p>\n<\/td>\n

\n

Meaning <\/p>\n

<\/b><\/p>\n<\/td>\n<\/tr>\n

\n

64 (0x40) <\/p>\n<\/td>\n

\n

Idle <\/p>\n<\/td>\n<\/tr>\n

\n

16384 (0x4000) <\/p>\n<\/td>\n

\n

Below Normal <\/p>\n<\/td>\n<\/tr>\n

\n

32 (0x20) <\/p>\n<\/td>\n

\n

Normal <\/p>\n<\/td>\n<\/tr>\n

\n

32768 (0x8000)<\/p>\n<\/td>\n

\n

Above Normal <\/p>\n<\/td>\n<\/tr>\n

\n

128 (0x80) <\/p>\n<\/td>\n

\n

High Priority <\/p>\n<\/td>\n<\/tr>\n

\n

256 (0x100) <\/p>\n<\/td>\n

\n

Real Time<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\n

 <\/p>\n<\/p>\n

To change the priority of a process, you need to connect directly to the process. The SetPriority<\/b> method is what is called an instance<\/b> method, and therefore we need to return an instance of a process. To do this, use the key<\/b> property of the class. The key<\/b> property for Win32_Process<\/b> is Handle<\/b> (MSDN reports the key property qualifier). Use the WMI class accelerator to connect to the specific instance of the WMI class. The code to do this is shown here:<\/p>\n

[wmi]”win32_process.handle=’4236′”<\/p>\n

<\/font><\/span><\/p>\n

When that line of code is run, the results appear that are shown in the following image.<\/p>\n

\"Image<\/p>\n

\n

 <\/p>\n<\/p>\n

Now that I know that the command is returning the exact Notepad process that I am interested in working with, it is time to call the SetPriority<\/b> method. To do this we modify the command just a little bit, as seen here where we change the priority of the Notepad process to a very low priority:<\/p>\n

PS C:> ([wmi]”win32_process.handle=’4236′”).setPriority(64)<\/p>\n

__GENUS          <\/span>: 2
__CLASS          <\/span>: __PARAMETERS
__SUPERCLASS     <\/span>:
__DYNASTY        <\/span>: __PARAMETERS
__RELPATH      <\/span>  <\/span>:
__PROPERTY_COUNT : 1
__DERIVATION     <\/span>: {}
__SERVER         <\/span>:
__NAMESPACE      <\/span>:
__PATH           <\/span>:
ReturnValue      <\/span>: 0<\/p>\n

PS C:><\/p>\n

<\/font><\/span><\/p>\n

 <\/p>\n

CS, that is all there is to using WMI to change the priority of a process. WMI Week will continue tomorrow when we will talk about…wait a minute. <\/p>\n

If you want to know exactly what we will be looking at tomorrow, follow us on Twitter<\/font><\/a> or Facebook<\/a>. If you have any questions, send e-mail to us at scripter@microsoft.com<\/font><\/a> or post your questions on the Official Scripting Guys Forum<\/a>. See you tomorrow. Until then, peace.<\/p>\n

<\/p>\n

 <\/p>\n

<\/span><\/p>\n

Ed Wilson and Craig Liebendorfer, Scripting Guys<\/p>\n

<\/span><\/b><\/p>\n

<\/span><\/b> <\/p>\n

<\/p>\n

 <\/p>\n

<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

    Hey, Scripting Guy! I have a problem with a rather annoying program at work. The program starts up and runs with high priority. When it does this, my computer is slow as a snail, and as unresponsive as a bear hibernating in the winter. I would like to use Windows PowerShell to lower […]<\/p>\n","protected":false},"author":595,"featured_media":87096,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[87,3,45],"class_list":["post-50673","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-scripting","tag-processes","tag-scripting-guy","tag-windows-powershell"],"acf":[],"blog_post_summary":"

    Hey, Scripting Guy! I have a problem with a rather annoying program at work. The program starts up and runs with high priority. When it does this, my computer is slow as a snail, and as unresponsive as a bear hibernating in the winter. I would like to use Windows PowerShell to lower […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts\/50673","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/users\/595"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/comments?post=50673"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/posts\/50673\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/media\/87096"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/media?parent=50673"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/categories?post=50673"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/scripting\/wp-json\/wp\/v2\/tags?post=50673"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}