scripts/trace: added script to annotate traces

This script will use the output generated by the spdk_trace app (JSON) and
replace some of the raw pointers with the information gathered through
the DTrace probes.

For now, this only prints out the traces without doing any annotations,
so the output should be nearly identical to what's printed by
spdk_trace.  The annotations will be added in subsequent patches.

Signed-off-by: Konrad Sztyber <konrad.sztyber@intel.com>
Change-Id: I406e8d4fde9cb88b31c38aa96f11b88e607e9436
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/8105
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>

scripts/bpf/trace.py

@@ -0,0 +1,115 @@
+#!/usr/bin/env python3
+
+from argparse import ArgumentParser
+from dataclasses import dataclass
+from typing import Dict, List, TypeVar
+import json
+import sys
+
+
+@dataclass
+class TracepointArgument:
+    """Describes an SPDK tracepoint argument"""
+    TYPE_INT = 0
+    TYPE_PTR = 1
+    TYPE_STR = 2
+    name: str
+    argtype: int
+
+
+@dataclass
+class Tracepoint:
+    """Describes an SPDK tracepoint, equivalent to struct spdk_trace_tpoint"""
+    name: str
+    id: int
+    new_object: bool
+    args: List[TracepointArgument]
+
+
+@dataclass
+class TraceEntry:
+    """Describes an SPDK tracepoint entry, equivalent to struct spdk_trace_entry"""
+    lcore: int
+    tpoint: Tracepoint
+    tsc: int
+    poller: str
+    size: int
+    object_id: str
+    object_ptr: int
+    time: int
+    args: Dict[str, TypeVar('ArgumentType', str, int)]
+
+
+class Trace:
+    """Stores, parses, and prints out SPDK traces"""
+    def __init__(self, file):
+        self._json = json.load(file)
+        self._argfmt = {TracepointArgument.TYPE_PTR: lambda a: f'0x{a:x}'}
+        self.tpoints = {t.id: t for t in self._parse_tpoints()}
+        self.tsc_rate = self._json['tsc_rate']
+
+    def _parse_tpoints(self):
+        for tpoint in self._json.get('tpoints', []):
+            yield Tracepoint(
+                name=tpoint['name'], id=tpoint['id'],
+                new_object=tpoint['new_object'],
+                args=[TracepointArgument(name=a['name'],
+                                         argtype=a['type'])
+                      for a in tpoint.get('args', [])])
+
+    def _parse_entry(self, entry):
+        tpoint = self.tpoints[entry['tpoint']]
+        obj = entry.get('object', {})
+        return TraceEntry(tpoint=tpoint, lcore=entry['lcore'], tsc=entry['tsc'],
+                          size=entry.get('size'), object_id=obj.get('id'),
+                          object_ptr=obj.get('value'), time=obj.get('time'),
+                          poller=entry.get('poller'),
+                          args={n.name: v for n, v in zip(tpoint.args, entry.get('args', []))})
+
+    def _entries(self):
+        for entry in self._json.get('entries', []):
+            yield self._parse_entry(entry)
+
+    def _format_args(self, entry):
+        args = []
+        for arg, (name, value) in zip(entry.tpoint.args, entry.args.items()):
+            args.append('{}: {}'.format(name, self._argfmt.get(arg.argtype,
+                                                               lambda a: a)(value)))
+        return args
+
+    def print(self):
+        def get_us(tsc, off):
+            return ((tsc - off) * 10 ** 6) / self.tsc_rate
+
+        offset = None
+        for e in self._entries():
+            offset = e.tsc if offset is None else offset
+            timestamp = get_us(e.tsc, offset)
+            diff = get_us(e.time, 0) if e.time is not None else None
+            args = ', '.join(self._format_args(e))
+            fields = [
+                f'{e.lcore:3}',
+                f'{timestamp:16.3f}',
+                f'{e.poller:3}' if e.poller is not None else ' ' * 3,
+                f'{e.tpoint.name:24}',
+                f'size: {e.size:6}' if e.size is not None else ' ' * (len('size: ') + 6),
+                f'id: {e.object_id:8}' if e.object_id is not None else None,
+                f'time: {diff:<8.3f}' if diff is not None else None,
+                args
+            ]
+
+            print(' '.join([*filter(lambda f: f is not None, fields)]).rstrip())
+
+
+def main(argv):
+    parser = ArgumentParser(description='SPDK trace annotation script')
+    parser.add_argument('-i', '--input',
+                        help='JSON-formatted trace file produced by spdk_trace app')
+    args = parser.parse_args(argv)
+
+    file = open(args.input, 'r') if args.input is not None else sys.stdin
+    Trace(file).print()
+
+
+if __name__ == '__main__':
+    main(sys.argv[1:])