Desktop Heap Overview

re: Desktop Heap Overview

gnolkha — Wed, 24 Apr 2013 01:43:08 GMT

Does someone know of a tool that will visually present raw data structures, for example in windbg ? And you should be able to search some keywords say DPC or interrupt and it should list all the hits on those.

[I'm not sure how this question relates to desktop heap. The x and dt commands accept wildcards. For example you can run "dt nt!*DPC*" to find functions and structures that include the string DPC.]

re: Desktop Heap Overview

Miroslav Reisinger — Thu, 30 Aug 2012 10:02:18 GMT

Hi guys, is there any official way how to check desktop heap utilization on Win2k8 and above except running !dskheap? What we did is that we captured complete memory dump but the !dskheap extension seems to be not working. I'm getting output like this (x64 W2k8 SP2, Win32k.sys desktop heap events logged in the system event log):

!dskheap

Error Reading rpdeskList from WINDOWSTATION @ fffffa800f1e9f60

Failed counting Desktops for Winsta @fffffa800f1e9f60

EnumDsktps failed on Winsta: f1e9f60FillWinstaArray failed

I have experienced this extension to fail many times in the past on different complete memory dumps from various OS versions. I have also tried older version of windbg/kd but it did not helped. Is there something that has to be enabled on the OS level on the system where you are suspecting desktop heap exhaustion or is it just a debugger bug?

[Either the information the extension needs is paged out, or you are not in the context of a process that has session space. Find a process in the session where you suspect desktop heap is exhausted (!process 0 0), and change the debugger context to that process (.process /p /r ProcessAddress). If this doesn't work, is the memory at fffffa800f1e9f60 valid? (dq, !pte)]

re: Desktop Heap Overview

Bollimuntha — Sat, 25 Aug 2012 04:48:59 GMT

Hi,

Your explanation is excellent. You defined our problem in last but not suggested any solution. Can you please provide solution.

If the services all run under another user account which logs on multiples times, each time acquiring a new LUID, there will be a new desktop heap created for every instance of the service, and session view space will eventually become exhausted.

[The article suggests that such services may be poorly designed. You may be able to tune the size of each heap by modifying the SharedSection values.]

re: Desktop Heap Overview

Thomas — Wed, 23 Nov 2011 08:55:54 GMT

Is there a possibility of describing how this works under Vista, and providing a Vista-compatible version of dheapmon?

I often have up to 20 IE tabs open on Vista, and with a few other applications (eg Outlook, Excel, Word), I seem to be hitting some resource limit, as new windows often fail to be created (unless I close some old ones).

[Thomas, thank you for your interest in this article. Unfortunately we do not have a publicly available version of dheapmon for Windows Vista. Most load based resource exhaustion issues are eliminated by using x64, this is the solution that most customers have adopted.]

re: Desktop Heap Overview

test — Wed, 23 Nov 2011 08:52:48 GMT

his was a great primer on a part of Windows memory management that is seldom covered. Thanks!

Could not find file ‘C:\WINDOWS\TEMP\..dll’

Elementary, my dear Dr. Watson — Sat, 18 Apr 2009 16:35:01 GMT

Sometimes customers open technical support cases because of this (apparently simple) issue: “System.Web.Services.

PGES-Windows NT Debugging Blog Live Chat (March 17, 2009)

Ntdebugging Blog — Tue, 31 Mar 2009 00:52:01 GMT

We’d like the thank everyone who attended the Windows NT Debugging Blog Live Chat two weeks ago. Here

PGES-Windows NT Debugging Blog Live Chat (March 17, 2009)

Ntdebugging Blog — Tue, 31 Mar 2009 00:52:01 GMT

We’d like the thank everyone who attended the Windows NT Debugging Blog Live Chat two weeks ago. Here

re: Desktop Heap Overview

lorraine — Wed, 03 Dec 2008 06:13:54 GMT

not sure if this is my problem. in vista home basic in ie after games i get 'out of memory line 19' or the number will change to a 4 digit . clicking ok usually makes it go but next thing i do it comes back. sometimes 2 or more before it quits????? any suggestions?

Heap exhaustion symptoms, but heap not exhausted

Marek Vokac — Wed, 26 Nov 2008 17:14:12 GMT

Hi, I too found this a great article. My pet mystery is this: On a 2003 Server running a database replication app (interactive, not service), I get symptoms of heap exhaustion.

Like - windows not repainted properly, fonts missing, tray icons floating all over the place. The app itself crashed and the eventlog contains one event - "Fatal Application Exit : System Object not created". The exhaustion problems persist until I log off and create a new TS session.

But: dheapmon shows a maximum level of 13.5% usage on that interactive desktop. When freshly started, it's at 4-5%, and it rises slowly, so it would seem that something is leaking. But crash at 13% ? and, neither Task Manager nor any other tool I've found shows any leaks (USER object, GDI, Page Pool, nonpaged, Virtual memory, you name it).

Do you have any ideas at all? Are there other explanations besides desktop heap exhaustion that would fit the symptoms?

best regards,

Marek