[PATCH v1 17/49] perf python: Port mem-phys-addr to perf module

[Ian Rogers]

Port mem-phys-addr.py to a standalone script in tools/perf/python/
using the perf.session API to read perf.data files and profile physical
memory access types against /proc/iomem.

Improvements compared to the legacy script:
- Parse the full indentation hierarchy of /proc/iomem into a parent-child
  tree of frozen IomemEntry dataclasses (instead of only top-level
  indent-0 ranges), resolving physical addresses to the most specific
  sub-range (such as Kernel code/data/bss inside System RAM) and rolling
  child counts up into parent totals.
- Support profiling multiple memory events in a single perf.data session
  (keyed by evsel name) instead of assuming a single global event.
- Add argparse CLI options (-i/--input and --iomem to allow supplying an
  offline /proc/iomem snapshot from a target system).

Add a shell test (test_mem_phys_addr_python.sh) to verify the standalone
script.

Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/python/mem-phys-addr.py            | 137 ++++++++++++++++++
 .../tests/shell/test_mem_phys_addr_python.sh  | 101 +++++++++++++
 2 files changed, 238 insertions(+)
 create mode 100755 tools/perf/python/mem-phys-addr.py
 create mode 100755 tools/perf/tests/shell/test_mem_phys_addr_python.sh

diff --git a/tools/perf/python/mem-phys-addr.py b/tools/perf/python/mem-phys-addr.py
new file mode 100755
index 000000000000..5064e673c6a2
--- /dev/null
+++ b/tools/perf/python/mem-phys-addr.py
@@ -0,0 +1,137 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+"""mem-phys-addr.py: Resolve physical address samples"""
+from __future__ import annotations
+import argparse
+import bisect
+import collections
+from dataclasses import dataclass
+import re
+from typing import (Dict, List, Optional)
+
+import perf
+
+@dataclass(frozen=True)
+class IomemEntry:
+    """Read from a line in /proc/iomem"""
+    begin: int
+    end: int
+    indent: int
+    label: str
+
+    def __lt__(self, other) -> bool:
+        if isinstance(other, int):
+            return self.begin < other
+        return self.begin < other.begin
+
+    def __gt__(self, other) -> bool:
+        if isinstance(other, int):
+            return self.begin > other
+        return self.begin > other.begin
+
+# Physical memory layout from /proc/iomem. Key is the indent and then
+# a list of ranges.
+iomem: Dict[int, List[IomemEntry]] = collections.defaultdict(list)
+# Child nodes from the iomem parent.
+children: Dict[IomemEntry, List[IomemEntry]] = collections.defaultdict(list)
+# Maximum indent seen before an entry in the iomem file.
+_STATE: Dict[str, int] = {"max_indent": 0}
+# Per-event counts for each range of memory.
+event_counts: Dict[str, collections.Counter] = collections.defaultdict(collections.Counter)
+
+def parse_iomem(iomem_path: str):
+    """Populate iomem from iomem file"""
+    with open(iomem_path, 'r', encoding='ascii') as f:
+        for line in f:
+            line = line.rstrip('\n')
+            if not line or line.isspace():
+                continue
+            indent = 0
+            while indent < len(line) and line[indent] == ' ':
+                indent += 1
+            _STATE["max_indent"] = max(_STATE["max_indent"], indent)
+            m = re.split('-|:', line, maxsplit=2)
+            if len(m) < 3:
+                continue
+            begin = int(m[0].strip(), 16)
+            end = int(m[1].strip(), 16)
+            label = m[2].strip()
+            entry = IomemEntry(begin, end, indent, label)
+            # Before adding entry, search for a parent node using its begin.
+            if indent > 0:
+                parent = find_memory_type(begin)
+                assert parent, f"Given indent expected a parent for {label}"
+                children[parent].append(entry)
+            iomem[indent].append(entry)
+
+def find_memory_type(phys_addr) -> Optional[IomemEntry]:
+    """Search iomem for the range containing phys_addr with the maximum indent"""
+    for i in range(_STATE["max_indent"], -1, -1):
+        if i not in iomem:
+            continue
+        position = bisect.bisect_right(iomem[i], phys_addr)
+        if position == 0:
+            continue
+        iomem_entry = iomem[i][position-1]
+        if  iomem_entry.begin <= phys_addr <= iomem_entry.end:
+            return iomem_entry
+    return None
+
+def _print_entries(entries, load_mem_type_cnt, total):
+    """Print counts from parents down to their children"""
+    for entry in sorted(entries,
+                        key=lambda e: (load_mem_type_cnt[e], e.begin),
+                        reverse=True):
+        count = load_mem_type_cnt[entry]
+        if count > 0:
+            mem_type = ' ' * entry.indent + f"{entry.begin:x}-{entry.end:x} : {entry.label}"
+            percent = 100 * count / total
+            print(f"{mem_type:<40}  {count:>10}  {percent:>10.1f}")
+            _print_entries(children[entry], load_mem_type_cnt, total)
+
+def print_memory_type():
+    """Print the resolved memory types and their counts."""
+    if not event_counts:
+        print("No valid physical address samples found in perf data.")
+        return
+
+    for event_name, load_mem_type_cnt in event_counts.items():
+        print(f"Event: {event_name}")
+        print(f"{'Memory type':<40}  {'count':>10}  {'percentage':>10}")
+        print(f"{'-' * 40:<40}  {'-' * 10:>10}  {'-' * 10:>10}")
+        total = sum(load_mem_type_cnt.values())
+        if total == 0:
+            continue
+
+        # Add count from children into the parent.
+        for i in range(_STATE["max_indent"], -1, -1):
+            if i not in iomem:
+                continue
+            for entry in iomem[i]:
+                for child in children[entry]:
+                    if load_mem_type_cnt[child] > 0:
+                        load_mem_type_cnt[entry] += load_mem_type_cnt[child]
+
+        _print_entries(iomem[0], load_mem_type_cnt, total)
+        print()
+if __name__ == "__main__":
+    ap = argparse.ArgumentParser(description="Resolve physical address samples")
+    ap.add_argument("-i", "--input", default="perf.data", help="Input file name")
+    ap.add_argument("--iomem", default="/proc/iomem", help="Path to iomem file")
+    args = ap.parse_args()
+
+    def process_event(sample):
+        """Process a single sample event."""
+        phys_addr = sample.sample_phys_addr or 0
+        if not phys_addr:
+            return
+        entry = find_memory_type(phys_addr)
+        if entry:
+            event_name = str(sample.evsel)
+            if event_name.startswith("evsel(") and event_name.endswith(")"):
+                event_name = event_name[6:-1]
+            event_counts[event_name][entry] += 1
+
+    parse_iomem(args.iomem)
+    perf.session(perf.data(args.input), sample=process_event).process_events()
+    print_memory_type()
diff --git a/tools/perf/tests/shell/test_mem_phys_addr_python.sh b/tools/perf/tests/shell/test_mem_phys_addr_python.sh
new file mode 100755
index 000000000000..ae2f2fba0d20
--- /dev/null
+++ b/tools/perf/tests/shell/test_mem_phys_addr_python.sh
@@ -0,0 +1,101 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# mem-phys-addr python test
+
+set -e
+
+shelldir=$(dirname "$0")
+# shellcheck source=lib/setup_python.sh
+. "${shelldir}"/lib/setup_python.sh
+
+# If we don't have the perf python module, we can't test
+if ! "$PYTHON" -c 'import perf' > /dev/null 2>&1; then
+	echo "Skipping test, perf python module not found"
+	exit 2
+fi
+
+script_dir="$(dirname "$0")/../../python"
+script_path="${script_dir}/mem-phys-addr.py"
+
+if [ ! -f "$script_path" ]; then
+	echo "Skipping test, mem-phys-addr.py not found at $script_path"
+	exit 2
+fi
+
+err=0
+temp_data=""
+temp_iomem=""
+temp_out=""
+
+cleanup() {
+	rm -f "${temp_data}" "${temp_iomem}" "${temp_out}"
+}
+
+trap 'cleanup' EXIT TERM INT
+
+temp_data=$(mktemp /tmp/perf.data.XXXXXX)
+temp_iomem=$(mktemp /tmp/perf.iomem.XXXXXX)
+temp_out=$(mktemp /tmp/perf.out.XXXXXX)
+
+cat << 'EOF' > "${temp_iomem}"
+00000000-ffffffffffffffff : System RAM
+  00000000-7fffffffffffffff : Low RAM
+    00001000-00ffffff : Kernel code
+  8000000000000000-ffffffffffffffff : High RAM
+EOF
+
+test_iomem_hierarchy() {
+	echo "Testing mem-phys-addr.py hierarchical iomem resolution..."
+	"$PYTHON" - "$script_path" "${temp_iomem}" << 'PYEOF' > "${temp_out}"
+import importlib.util
+import sys
+
+spec = importlib.util.spec_from_file_location("mem_phys_addr", sys.argv[1])
+mod = importlib.util.module_from_spec(spec)
+sys.modules[spec.name] = mod
+spec.loader.exec_module(mod)
+
+mod.parse_iomem(sys.argv[2])
+entry_kernel = mod.find_memory_type(0x100000)
+entry_high = mod.find_memory_type(0x9000000000000000)
+assert entry_kernel is not None and entry_kernel.label == "Kernel code"
+assert entry_high is not None and entry_high.label == "High RAM"
+mod.event_counts["cpu/mem-loads/"][entry_kernel] += 3
+mod.event_counts["cpu/mem-loads/"][entry_high] += 1
+mod.print_memory_type()
+PYEOF
+	if ! grep -q "System RAM" "${temp_out}" || \
+	   ! grep -q "Kernel code" "${temp_out}" || \
+	   ! grep -q "High RAM" "${temp_out}"; then
+		echo "Hierarchical iomem resolution test failed."
+		err=1
+	else
+		echo "Hierarchical iomem resolution test passed."
+	fi
+}
+
+test_file_mode() {
+	echo "Testing mem-phys-addr.py file mode..."
+
+	# Generate memory access events (try unprivileged user-space first, then system-wide)
+	if ! perf record --phys-data -d -o "${temp_data}" \
+	     -- perf test -w datasym >/dev/null 2>&1 && \
+	   ! perf record -d -o "${temp_data}" -- perf test -w datasym >/dev/null 2>&1 && \
+	   ! perf record -d -a -o "${temp_data}" -- sleep 0.2 >/dev/null 2>&1; then
+		echo "Skipping file mode record test, perf record -d not supported"
+		return 0
+	fi
+
+	# Run the script with custom --iomem
+	if ! "$PYTHON" "$script_path" -i "${temp_data}" --iomem "${temp_iomem}" >/dev/null; then
+		echo "File mode test failed."
+		err=1
+	else
+		echo "File mode test passed."
+	fi
+}
+
+test_iomem_hierarchy
+test_file_mode
+
+exit $err
-- 
2.55.0.1082.g2b9226bbc0-goog