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Tue, 28 Apr 2026 00:20:58 -0700 (PDT) Date: Tue, 28 Apr 2026 00:18:55 -0700 In-Reply-To: <20260428071903.1886173-1-irogers@google.com> Mime-Version: 1.0 References: <20260425224951.174663-1-irogers@google.com> <20260428071903.1886173-1-irogers@google.com> X-Mailer: git-send-email 2.54.0.545.g6539524ca2-goog Message-ID: <20260428071903.1886173-51-irogers@google.com> Subject: [PATCH v8 50/58] perf rwtop: Port rwtop to use python module From: Ian Rogers To: acme@kernel.org, namhyung@kernel.org Cc: adrian.hunter@intel.com, alice.mei.rogers@gmail.com, dapeng1.mi@linux.intel.com, james.clark@linaro.org, leo.yan@linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, tmricht@linux.ibm.com, Ian Rogers Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260428_082101_366226_691CAEEF X-CRM114-Status: GOOD ( 21.68 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Port the legacy Perl script rwtop.pl to a python script using the perf module in tools/perf/python. The new script uses a class-based architecture and leverages the perf.session API for event processing. It periodically displays system-wide r/w call activity, broken down by PID, refreshed every interval. Complications: - Implemented periodic display based on event timestamps (sample.sample_time) instead of relying on SIGALRM, making it robust for file-based processing. - Used ANSI escape codes (\x1b[H\x1b[2J) to clear the terminal. - Fixed unused imports and indentation issues identified by pylint. - pylint warns about the module name not being snake_case, but it is kept for consistency with the original script name. Assisted-by: Gemini:gemini-3.1-pro-preview Signed-off-by: Ian Rogers --- v2: - Added Live Session Support: Updated main() to start a LiveSession when the input file does not exist (or is the default "perf.data" and doesn't exist). It traces read and write entry/exit tracepoints. - Fixed Live Mode Comm Resolution: Fixed a bug in process_event() where it would attempt to use self.session to resolve the command name when running in live mode (where self.session is None ). It now falls back to f"PID({pid})" when in live mode or if resolution fails. - Fixed Substring Matching: Replaced loose substring checks like if "sys_enter_read" in event_name: with exact matches against "evsel(syscalls:sys_enter_read)" and "evsel(raw_syscalls:sys_enter_read)" using str(sample.evsel) . This prevents unrelated syscalls with similar names (like readv or readahead ) from being incorrectly aggregated. Similar fixes were applied for exit events and write events. - Inlined Handlers and Tracked Errors: Inlined the _handle_sys_* helper methods into process_event() . Now, if a sample lacks expected fields, it is added to the self.unhandled tracker instead of being silently ignored. - Fixed Write Byte Counting: Updated the write exit handler to use sample.ret to count actual bytes written on success, and tracked requested bytes separately in the enter handler, matching the read behavior. - Added Error Tables to Output: Added tables to display failed reads and writes by PID in print_totals() , which were previously tracked but never displayed. - Fixed Offline Output (Ghosting): Removed the hardcoded ANSI clear-screen escape codes in print_totals() , as they corrupted output when processing offline trace files at CPU speed or when piping the output. - Code Cleanup: Fixed a bug where fd was printed instead of pid in the read counts table, and broke long lines to satisfy pylint. --- tools/perf/python/rwtop.py | 219 +++++++++++++++++++++++++++++++++++++ 1 file changed, 219 insertions(+) create mode 100755 tools/perf/python/rwtop.py diff --git a/tools/perf/python/rwtop.py b/tools/perf/python/rwtop.py new file mode 100755 index 000000000000..895ebab9af10 --- /dev/null +++ b/tools/perf/python/rwtop.py @@ -0,0 +1,219 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0-only +"""Periodically displays system-wide r/w call activity, broken down by pid.""" + +import argparse +from collections import defaultdict +import os +import sys +from typing import Optional, Dict, Any +import perf +from perf_live import LiveSession + +class RwTop: + """Periodically displays system-wide r/w call activity.""" + def __init__(self, interval: int = 3, nlines: int = 20) -> None: + self.interval_ns = interval * 1000000000 + self.nlines = nlines + self.reads: Dict[int, Dict[str, Any]] = defaultdict( + lambda: { + "bytes_requested": 0, + "bytes_read": 0, + "total_reads": 0, + "comm": "", + "errors": defaultdict(int), + } + ) + self.writes: Dict[int, Dict[str, Any]] = defaultdict( + lambda: { + "bytes_requested": 0, + "bytes_written": 0, + "total_writes": 0, + "comm": "", + "errors": defaultdict(int), + } + ) + self.unhandled: Dict[str, int] = defaultdict(int) + self.session: Optional[perf.session] = None + self.last_print_time: int = 0 + + def process_event(self, sample: perf.sample_event) -> None: # pylint: disable=too-many-branches + """Process events.""" + event_name = str(sample.evsel) + pid = sample.sample_pid + sample_time = sample.sample_time + + if self.last_print_time == 0: + self.last_print_time = sample_time + + # Check if interval has passed + if sample_time - self.last_print_time >= self.interval_ns: + self.print_totals() + self.last_print_time = sample_time + + try: + comm = f"PID({pid})" if not self.session else self.session.find_thread(pid).comm() + except Exception: # pylint: disable=broad-except + comm = f"PID({pid})" + + if event_name in ("evsel(syscalls:sys_enter_read)", "evsel(raw_syscalls:sys_enter_read)"): + try: + count = sample.count + self.reads[pid]["bytes_requested"] += count + self.reads[pid]["total_reads"] += 1 + self.reads[pid]["comm"] = comm + except AttributeError: + self.unhandled[event_name] += 1 + elif event_name in ("evsel(syscalls:sys_exit_read)", "evsel(raw_syscalls:sys_exit_read)"): + try: + ret = sample.ret + if ret > 0: + self.reads[pid]["bytes_read"] += ret + else: + self.reads[pid]["errors"][ret] += 1 + except AttributeError: + self.unhandled[event_name] += 1 + elif event_name in ("evsel(syscalls:sys_enter_write)", + "evsel(raw_syscalls:sys_enter_write)"): + try: + count = sample.count + self.writes[pid]["bytes_requested"] += count + self.writes[pid]["total_writes"] += 1 + self.writes[pid]["comm"] = comm + except AttributeError: + self.unhandled[event_name] += 1 + elif event_name in ("evsel(syscalls:sys_exit_write)", "evsel(raw_syscalls:sys_exit_write)"): + try: + ret = sample.ret + if ret > 0: + self.writes[pid]["bytes_written"] += ret + else: + self.writes[pid]["errors"][ret] += 1 + except AttributeError: + self.unhandled[event_name] += 1 + else: + self.unhandled[event_name] += 1 + + def print_totals(self) -> None: + """Print summary tables.""" + print("read counts by pid:\n") + print( + f"{'pid':>6s} {'comm':<20s} {'# reads':>10s} " + f"{'bytes_req':>10s} {'bytes_read':>10s}" + ) + print(f"{'-'*6} {'-'*20} {'-'*10} {'-'*10} {'-'*10}") + + count = 0 + for pid, data in sorted(self.reads.items(), + key=lambda kv: kv[1]["bytes_read"], reverse=True): + print( + f"{pid:6d} {data['comm']:<20s} {data['total_reads']:10d} " + f"{data['bytes_requested']:10d} {data['bytes_read']:10d}" + ) + count += 1 + if count >= self.nlines: + break + + print("\nfailed reads by pid:\n") + print(f"{'pid':>6s} {'comm':<20s} {'error #':>6s} {'# errors':>10s}") + print(f"{'-'*6} {'-'*20} {'-'*6} {'-'*10}") + + errcounts = [] + for pid, data in self.reads.items(): + for error, cnt in data["errors"].items(): + errcounts.append((pid, data["comm"], error, cnt)) + + sorted_errcounts = sorted(errcounts, key=lambda x: x[3], reverse=True) + for pid, comm, error, cnt in sorted_errcounts[:self.nlines]: + print(f"{pid:6d} {comm:<20s} {error:6d} {cnt:10d}") + + print("\nwrite counts by pid:\n") + print( + f"{'pid':>6s} {'comm':<20s} {'# writes':>10s} " + f"{'bytes_req':>10s} {'bytes_written':>13s}" + ) + print(f"{'-'*6} {'-'*20} {'-'*10} {'-'*10} {'-'*13}") + + count = 0 + for pid, data in sorted(self.writes.items(), + key=lambda kv: kv[1]["bytes_written"], reverse=True): + print( + f"{pid:6d} {data['comm']:<20s} {data['total_writes']:10d} " + f"{data['bytes_requested']:10d} {data['bytes_written']:13d}" + ) + count += 1 + if count >= self.nlines: + break + + print("\nfailed writes by pid:\n") + print(f"{'pid':>6s} {'comm':<20s} {'error #':>6s} {'# errors':>10s}") + print(f"{'-'*6} {'-'*20} {'-'*6} {'-'*10}") + + errcounts = [] + for pid, data in self.writes.items(): + for error, cnt in data["errors"].items(): + errcounts.append((pid, data["comm"], error, cnt)) + + sorted_errcounts = sorted(errcounts, key=lambda x: x[3], reverse=True) + for pid, comm, error, cnt in sorted_errcounts[:self.nlines]: + print(f"{pid:6d} {comm:<20s} {error:6d} {cnt:10d}") + + # Reset counts + self.reads.clear() + self.writes.clear() + + def run(self, input_file: str) -> None: + """Run the session.""" + self.session = perf.session(perf.data(input_file), sample=self.process_event) + self.session.process_events() + + # Print final totals if there are any left + if self.reads or self.writes: + self.print_totals() + + if self.unhandled: + print("\nunhandled events:\n") + print(f"{'event':<40s} {'count':>10s}") + print(f"{'-'*40} {'-'*10}") + for event_name, count in self.unhandled.items(): + print(f"{event_name:<40s} {count:10d}") + +def main() -> None: + """Main function.""" + parser = argparse.ArgumentParser(description="Trace r/w activity by PID") + parser.add_argument( + "interval", type=int, nargs="?", default=3, help="Refresh interval in seconds" + ) + parser.add_argument("-i", "--input", default="perf.data", help="Input file") + args = parser.parse_args() + + analyzer = RwTop(args.interval) + try: + if not os.path.exists(args.input) and args.input == "perf.data": + # Live mode + events = ( + "syscalls:sys_enter_read,syscalls:sys_exit_read," + "syscalls:sys_enter_write,syscalls:sys_exit_write" + ) + try: + live_session = LiveSession(events, sample_callback=analyzer.process_event) + except OSError: + events = ( + "raw_syscalls:sys_enter_read,raw_syscalls:sys_exit_read," + "raw_syscalls:sys_enter_write,raw_syscalls:sys_exit_write" + ) + live_session = LiveSession(events, sample_callback=analyzer.process_event) + print("Live mode started. Press Ctrl+C to stop.", file=sys.stderr) + live_session.run() + else: + analyzer.run(args.input) + except IOError as e: + print(e, file=sys.stderr) + sys.exit(1) + except KeyboardInterrupt: + print("\nStopping live mode...", file=sys.stderr) + if analyzer.reads or analyzer.writes: + analyzer.print_totals() + +if __name__ == "__main__": + main() -- 2.54.0.545.g6539524ca2-goog