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Bug #1131

enable-event doesn't match class unless using wildcard

Added by Tom Deseyn about 3 years ago. Updated about 3 years ago.

Status:
Resolved
Priority:
Normal
Target version:
-
Start date:
10/04/2017
Due date:
% Done:

0%

Estimated time:

Description

I am tracing a .NET Core application. The runtime uses lttng ust and emits events named 'DotNETRuntime:*'.

I am interested in the 'DotNETRuntime:GCAllocationTick_V3' event.
When I 'enable-event DotNETRuntime:GCAllocationTick_V3' it is not part of the trace.
When I enable the more general 'DotNETRuntime:*', 'DotNETRuntime:GCAllocationTick_V3' is in the trace.
When I enable event 'DotNETRuntime:RuntimeInformationStart' (without enabling the wildcard), 'DotNETRuntime:RuntimeInformationStart' in the trace.

I don't understand why tracing works for DotNETRuntime:RuntimeInformationStart but not for DotNETRuntime:GCAllocationTick_V3.

Below you see an attempt to trace 'DotNETRuntime:GCAllocationTick_V3' followed by an attempt when using 'DotNETRuntime:*'.
The dotnet application is started after 'lttng start', and terminates before executing 'lttng stop'.

Attempt 'DotNETRuntime:GCAllocationTick_V3':
```
$ lttng create
Session auto-20171004-111626 created.
Traces will be written in /home/tmds/lttng-traces/auto-20171004-111626
$ lttng enable-event --userspace DotNETRuntime:GCAllocationTick_V3
UST event DotNETRuntime:GCAllocationTick_V3 created in channel channel0
$ lttng start
Tracing started for session auto-20171004-111626
$ lttng list auto-20171004-111626
Tracing session auto-20171004-111626: [active]
Trace path: /home/tmds/lttng-traces/auto-20171004-111626

=== Domain: UST global ===

Buffer type: per UID

Channels:
-------------
- channel0: [enabled]

Attributes:
overwrite mode: 0
subbuffers size: 131072
number of subbuffers: 4
switch timer interval: 0
read timer interval: 0
trace file count: 0
trace file size (bytes): 0
discarded events: 0
lost packets: 0
output: mmap()
Events:
DotNETRuntime:GCAllocationTick_V3 (type: tracepoint) [enabled]

$ lttng stop
Waiting for data availability.
Tracing stopped for session auto-20171004-111626
$ lttng destroy
Session auto-20171004-111626 destroyed
$ babeltrace /home/tmds/lttng-traces/auto-20171004-111626
<nothing>
```

Attempt 'DotNETRuntime:*':
```
$ lttng create
Session auto-20171004-112647 created.
Traces will be written in /home/tmds/lttng-traces/auto-20171004-112647
$ lttng enable-event --userspace DotNETRuntime:*
UST event DotNETRuntime:* created in channel channel0
$ lttng start
Tracing started for session auto-20171004-112647
$ lttng list auto-20171004-112647
Tracing session auto-20171004-112647: [active]
Trace path: /home/tmds/lttng-traces/auto-20171004-112647

=== Domain: UST global ===

Buffer type: per UID

Channels:
-------------
- channel0: [enabled]

Attributes:
overwrite mode: 0
subbuffers size: 131072
number of subbuffers: 4
switch timer interval: 0
read timer interval: 0
trace file count: 0
trace file size (bytes): 0
discarded events: 0
lost packets: 0
output: mmap()
Events:
DotNETRuntime:* (type: tracepoint) [enabled]

$ lttng stop
Waiting for data availability.
[warning] 7305 events discarded, please refer to the documentation on channel configuration.
Tracing stopped for session auto-20171004-112647
$ lttng destroy
Session auto-20171004-112647 destroyed
$ babeltrace /home/tmds/lttng-traces/auto-20171004-112647 | grep DotNETRuntime:GCAllocationTick_V3
[11:27:16.666713244] (+0.000006752) puter DotNETRuntime:GCAllocationTick_V3: { cpu_id = 4 }, { AllocationAmount = 108352, AllocationKind = 0, ClrInstanceID = 0, AllocationAmount64 = 108352, TypeID = 140150218098888, TypeName = "System.Int32[]", HeapIndex = 0, Address = 140149547677912 }
[11:27:16.669621317] (+0.000006642) puter DotNETRuntime:GCAllocationTick_V3: { cpu_id = 4 }, { AllocationAmount = 104032, AllocationKind = 0, ClrInstanceID = 0, AllocationAmount64 = 104032, TypeID = 140150218406064, TypeName = "System.Object", HeapIndex = 0, Address = 140149547770848 }
```

System info:
```
$ lttng --version
lttng (LTTng Trace Control) 2.8.1 - Isseki Nicho
$ uname -a
Linux puter 4.11.8-200.fc25.x86_64 #1 SMP Thu Jun 29 16:13:56 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
$ dotnet --version
2.0.0
```

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