bpftrace/bpftrace

AI Summary: Migrate existing USDT test programs within the bpftrace project from a vendored SystemTap file to utilize the newer, supported libbpf/usdt library. This involves refactoring the test programs to use the libbpf/usdt API for interacting with USDT probes.

AI Summary: The task is to debug a bpftrace issue where the `self:*` probe type, when used with the `-l` (list) option, produces unexpected error messages instead of the expected list of available probes. The issue needs investigation to determine why the error handling for `self` probes differs from other probe types when listing available probes. The solution likely involves examining the bpftrace codebase to identify and correct the error in the probe listing logic for `self` probes.

AI Summary: Implement a `--probe-filter` command-line option for bpftrace, allowing users to selectively run probes within a script using a string or glob pattern. This is needed to support new BENCH and TEST probes and improve testing and benchmarking capabilities.

AI Summary: Modify the bpftrace symbol caching mechanism to only cache symbols from processes explicitly targeted using the "-p" flag. Currently, when "per_pid" caching is enabled, symbols are cached for all instances of a process, even if only a subset is being traced. The improvement should reduce startup time and memory usage for scenarios involving tracing specific processes.