Allow running without syscall tracepoints #2990
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Currently we fail to run if tracepoints can't be set on various sub-events of /sys/kernel/debug/tracing/events/syscalls/ . Currently these are only used to detect process exit, so with --disable-tracepoints we will not detect that as quickly/precisely, leading to bloat in the BPF maps. Without tracepoints, we will only detect exited processes every pidCleanupInterval (by default 5 minutes), through a scan of /proc. Thus setting this flag is not recommended unless necessary. It might be necessary because certain obscure distributions apparently run with a configuration that doesn't expost these syscall tracepoint events. I have confirmed that with this patch (and setting the flag), the agent starts up and seems to work normally on a kernel without CONFIG_FTRACE_SYSCALLS, which fails without this patch.
|
|
umanwizard
changed the title
1. Get rid of the flag; unconditionally continue attempting to run even if ProbeTracepoint fails. 2. Don't gate attaching the scheduling monitor; this is available even when syscall probes aren't.
|
The Otel agent has exactly the same issue: open-telemetry/opentelemetry-ebpf-profiler#173 We don't necessarily need to do the same thing as them, since this is entirely controlled within our own |
brancz
approved these changes
Oct 9, 2024
|
There were no strong objections on the OTel issue so I think this can be merged. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Currently we fail to run if tracepoints can't be set on various sub-events of /sys/kernel/debug/tracing/events/syscalls/ . Currently these are used to detect various offsets when BTF is not available.
Since some kernel configurations don't have syscall tracepoints, but do have BTF info, things might still work if we just keep running here.
I have confirmed that with this patch, the agent starts up and seems to work normally on a kernel without CONFIG_FTRACE_SYSCALLS, which fails without this patch.