tools/testing/selftests/rseq/rseq-slice-hist.py

Source file repositories/reference/linux-study-clean/tools/testing/selftests/rseq/rseq-slice-hist.py

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/rseq/rseq-slice-hist.py
Extension
.py
Size
3629 bytes
Lines
133
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: tools
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

#!/usr/bin/python3

#
# trace-cmd record -e hrtimer_start -e hrtimer_cancel -e hrtimer_expire_entry -- $cmd
#

from tracecmd import *

def load_kallsyms(file_path='/proc/kallsyms'):
    """
    Parses /proc/kallsyms into a dictionary.
    Returns: { address_int: symbol_name }
    """
    kallsyms_map = {}

    try:
        with open(file_path, 'r') as f:
            for line in f:
                # The format is: [address] [type] [name] [module]
                parts = line.split()
                if len(parts) < 3:
                    continue

                addr = int(parts[0], 16)
                name = parts[2]

                kallsyms_map[addr] = name

    except PermissionError:
        print(f"Error: Permission denied reading {file_path}. Try running with sudo.")
    except FileNotFoundError:
        print(f"Error: {file_path} not found.")

    return kallsyms_map

ksyms = load_kallsyms()

# pending[timer_ptr] = {'ts': timestamp, 'comm': comm}
pending = {}

# histograms[comm][bucket] = count
histograms = {}

class OnlineHarmonicMean:
    def __init__(self):
        self.n = 0          # Count of elements
        self.S = 0.0        # Cumulative sum of reciprocals

    def update(self, x):
        if x == 0:
            raise ValueError("Harmonic mean is undefined for zero.")

        self.n += 1
        self.S += 1.0 / x
        return self.n / self.S

    @property
    def mean(self):
        return self.n / self.S if self.n > 0 else 0

ohms = {}

def handle_start(record):
    func_name = ksyms[record.num_field("function")]
    if "rseq_slice_expired" in func_name:
        timer_ptr = record.num_field("hrtimer")
        pending[timer_ptr] = {
            'ts': record.ts,
            'comm': record.comm
        }

Annotation

Implementation Notes