Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Lack of LTTngCds implementation? #104

Closed
ami-GS opened this issue Dec 17, 2022 · 1 comment
Closed

Lack of LTTngCds implementation? #104

ami-GS opened this issue Dec 17, 2022 · 1 comment

Comments

@ami-GS
Copy link

ami-GS commented Dec 17, 2022

Hi Team,

I'm writing MsQuic LTTng trace extension for WPA.
microsoft/msquic#3294

I noticed lack of information in LTTngEvent which is actually in trace file.
As in image, vpid and vtid are stored in LTTngEvent.StreamDefinedEventContext as “_vpid” and “_vtid”.
However there is no cpu_id information which is stored in as stream.packet.context
Is this lack of LTTngCds implementation?

One of trace
quic.babel.txt
The trace file exactly has cpu_id in stream.packet.context
image
The cpu_id is not stored in LTTngEvent
image

@ivberg
Copy link
Contributor

ivberg commented Dec 19, 2022

Indeed, it looks like we don’t directly process cpu_id from stream packet context. I am not sure the original reason for that decision but maybe perf so we don't need to read it every time.

However, we do provide the CPU Id information based on reading the cpu from the channel name format – e.g. (channel0_11 is CPU 11). They should be equivalent.

This is available in LTTngContext CurrentCpu. I will add a unit test showing how this is exposed

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

No branches or pull requests

2 participants