Attach .Net Profiler at RunTime to a running process

Rajeshwari kanchiraju 1

Hi ,

I have been trying to attach the .Net Profiler at Runtime to a running process using the PID information .

I could able to use attachprofiler() method and call Initializeforattach() method.

Im trying to set the masks -"COR_PRF_ENABLE_REJIT" & "COR_PRF_DISABLE_ALL_NGEN_IMAGES" inside the initializeforattach() method using "SetEventMask()" method but its getting failed.

Inside the Initializeforattach() , I have used "ICorProfilerInfo4" object for QueryInterface().

@Brian Please help me why seteventmasks() getting failed and unable to load the modules.

Any reference is much appreciated.

Thanks in advance.

Xingyu Zhao-MSFT 5,356 Reputation points

2021-11-04T06:02:56.557+00:00

Hi @Rajeshwari kanchiraju ,
In order to help us analyze the problem, could you share more related code here?
We are waiting for your update.
Rajeshwari kanchiraju 1 Reputation point

2021-11-08T03:16:30.83+00:00

Hi @Xingyu Zhao-MSFT

Thanks for your reply.

I'm trying to set the event masks in the Initializeforattach() for "COR_PRF_ENABLE_REJIT" which is getting failed, Here is the below code snippet which I have used

InitializeForAttach(
/* [in] */ IUnknown pICorProfilerInfoUnk,
/ [in] */ void pvClientData,
/ [in] */ UINT cbClientData)
{ HRESULT hr;
hr = pICorProfilerInfoUnk->QueryInterface(IID_ICorProfilerInfo4, (void )&m_pProfilerInfo4);
hr = pICorProfilerInfoUnk->QueryInterface(IID_ICorProfilerInfo3, (void **)&m_pProfilerInfo3);
hr = pICorProfilerInfoUnk->QueryInterface(IID_ICorProfilerInfo2, (void **)&m_pProfilerInfo);
.
.
.
.
.
**hr = m_pProfilerInfo->SetEventMask( COR_PRF_MONITOR_JIT_COMPILATION |COR_PRF_MONITOR_MODULE_LOADS|COR_PRF_MONITOR_MODULE_LOADS|COR_PRF_ENABLE_REJIT | COR_PRF_DISABLE_ALL_NGEN_IMAGES );
.
.
.
.
}

Please help me if i would have missed anything
Xingyu Zhao-MSFT 5,356 Reputation points

2021-11-09T06:15:47.67+00:00

Hi @Rajeshwari kanchiraju ,
I note that SetEventMask2 is the recommended alternative to the SetEventMask method, so you can use SetEventMask2 method to do it.
Rajeshwari kanchiraju 1 Reputation point

2021-11-09T12:16:24.563+00:00

Hi @Xingyu Zhao-MSFT ,

SetEventMask2 is also doing the same. Its getting failed when I'm trying to set mask "COR_PRF_ENABLE_REJIT"

I have developed my own .Net profiler for instrumenting the .net applications. Now I am trying to attach the profiler to an instrument already running w3wp.exe.

Since all the Modules have been already loaded, Couldn't able to get the callbacks for JITCompilation.
Hence to re-compile, the methods I am trying to use ICorProfilerInfo interfaces to trigger the "RequestReJIT Method". Could you please help us to know how to trigger RequestReJIT to load the modules again so that we can instrument the .Net applications while attaching at runtime?
Xingyu Zhao-MSFT 5,356 Reputation points

2021-11-10T05:41:47.233+00:00

Hi @Rajeshwari kanchiraju ,
Take a look at the following blog.
ReJIT: A How-To Guide
Hope it could be helpful to your question.
Rajeshwari kanchiraju 1 Reputation point

2021-11-12T08:29:25.657+00:00

Hi @Xingyu Zhao-MSFT ,

Thanks for the reference, I have tried setting up masks as suggested in the guide. I could set the event mask inside the initialize() method but the ReJIT APIs are not able to call even the seteventmasks() for ReJIT is successful. Could you please share the information at which condition "ICorProfilerCallback4::ReJITCompilationStarted Method is triggered or called and where exactly "ICorProfilerInfo4::RequestReJIT Method" should be called? we didn't get enough information in the guide. any references for Triggering the "ReJITCompilationStarted" method and the right place for calling the "RequestReJIT" method is much helpful.
Xingyu Zhao-MSFT 5,356 Reputation points

2021-11-15T07:10:59.827+00:00

Hi @Rajeshwari kanchiraju ,
I regret that I'm not familiar with .Net Profiler. You can also post your question about profiler on this forum.
Besides, for attaching a profiler to a process at runtime, there's a blog about it.
CLR V4: Profiler Attach Basics With Sample Code
Unfortunately, since the blog was written many years ago, all links are dead