guest-diag: stream uvmt sems over vsock (no guest-agent race); dump channel last release VA; larger push log budget

1 files changed, 48 insertions, 12 deletions

diff --git a/tools/guest-diag/guest_pin_stream.py b/tools/guest-diag/guest_pin_stream.py
index bb3f99a..1ff0d3f 100644
--- a/tools/guest-diag/guest_pin_stream.py
+++ b/tools/guest-diag/guest_pin_stream.py
@@ -11,7 +11,9 @@
 #
 # Usage: sudo python3 guest_pin_stream.py [host-cid] [port] [lo-hex] [hi-hex] [pa-max-hex]
 import os
+import re
 import socket
+import subprocess
 import sys
 import time
 
@@ -24,6 +26,30 @@ INTERVAL = float(os.environ.get("STREAM_INTERVAL", "0.25"))
 BATCH = 4096
 REGION = 0x200000
 SPAN = int(os.environ.get("STREAM_SPAN", "0x10000"), 16)
+TRACE = ("/sys/kernel/tracing/trace"
+         if os.path.exists("/sys/kernel/tracing/trace")
+         else "/sys/kernel/debug/tracing/trace")
+SEM_EVERY = int(os.environ.get("STREAM_SEM_EVERY", "4"))
+
+
+def new_sems(seen):
+    """New tracking-sem kptrs (uvmt lines) in the trace tail.
+
+    Read in the guest so the host does not need a guest-agent round trip for
+    every semaphore discovery; the trace is only tailed while a client runs.
+    """
+    try:
+        out = subprocess.run(["tail", "-c", "262144", TRACE],
+                             capture_output=True, timeout=10).stdout
+    except Exception:
+        return []
+    found = []
+    for m in re.finditer(rb"sem=0x([0-9a-fA-F]+)", out):
+        v = int(m.group(1), 16)
+        if v not in seen:
+            seen.add(v)
+            found.append(v)
+    return found
 
 
 def cdt_pid():
@@ -82,18 +108,23 @@ def main():
         f.write('%d\n' % os.getpid())
     sock = None
     seen = {}
+    seen_sems = set()
     last_pid = None
     last_log = 0.0
+    loop = 0
     while True:
         pid = cdt_pid()
+        loop += 1
         if pid is None:
             last_pid = None
             seen = {}
+            seen_sems = set()
             time.sleep(INTERVAL)
             continue
         if pid != last_pid:
             last_pid = pid
             seen = {}
+            seen_sems = set()
             if sock is not None:
                 try:
                     sock.sendall(("#pid %d\n" % pid).encode())
@@ -109,28 +140,33 @@ def main():
         dt = time.time() - t0
         new = [(va, pa) for va, pa in cur.items() if seen.get(va) != pa]
         seen = cur
+        lines = []
+        if loop % SEM_EVERY == 0:
+            for sem in new_sems(seen_sems):
+                lines.append('#sem 0x%x\n' % sem)
         now = time.time()
         if now - last_log > 1.0:
             last_log = now
             try:
                 with open('/tmp/guest_pin_stream.log', 'a') as f:
-                    f.write('%s pid=%s present=%d new=%d scan=%.3fs\n'
-                            % (time.strftime('%T'), pid, len(cur), len(new), dt))
+                    f.write('%s pid=%s present=%d new=%d sem=%d scan=%.3fs\n'
+                            % (time.strftime('%T'), pid, len(cur), len(new),
+                               len(seen_sems), dt))
             except OSError:
                 pass
-        if not new:
+        if not new and not lines:
             time.sleep(INTERVAL)
             continue
-        new.sort()
-        lines = []
-        va0, pa0, n = new[0][0], new[0][1], 1
-        for va, pa in new[1:]:
-            if va == va0 + n * 0x1000 and pa == pa0 + n * 0x1000:
-                n += 1
-                continue
+        if new:
+            new.sort()
+            va0, pa0, n = new[0][0], new[0][1], 1
+            for va, pa in new[1:]:
+                if va == va0 + n * 0x1000 and pa == pa0 + n * 0x1000:
+                    n += 1
+                    continue
+                lines.append('0x%x,0x%x,%d\n' % (va0, pa0, n))
+                va0, pa0, n = va, pa, 1
             lines.append('0x%x,0x%x,%d\n' % (va0, pa0, n))
-            va0, pa0, n = va, pa, 1
-        lines.append('0x%x,0x%x,%d\n' % (va0, pa0, n))
         payload = ''.join(lines).encode()
         if sock is None:
             try: