From: mpi <mpi@openbsd.org>
Date: Sat, 23 Oct 2021 19:37:35 +0000 (+0000)
Subject: Provide common btrace(8) scripts.
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=1d4c37715e2edbda4c914ca87a1e809e2442a1e7;p=openbsd

Provide common btrace(8) scripts.

. kprofile.bt - to save kernel stackframces and produce flamegraphs
. runqlat.bt  - to measure the latency of the scheduler runqueues
---

diff --git a/share/btrace/Makefile b/share/btrace/Makefile
new file mode 100644
index 00000000000..900b5f69570
--- /dev/null
+++ b/share/btrace/Makefile
@@ -0,0 +1,10 @@
+#	$OpenBSD: Makefile,v 1.1 2021/10/23 19:37:35 mpi Exp $
+
+FILES=	kprofile.bt runqlat.bt
+NOOBJ=	noobj
+
+install:
+	${INSTALL} ${INSTALL_COPY} -o ${BINOWN} -g ${BINGRP} -m 444 ${FILES} \
+	    ${DESTDIR}${BINDIR}/btrace
+
+.include <bsd.prog.mk>
diff --git a/share/btrace/kprofile.bt b/share/btrace/kprofile.bt
new file mode 100644
index 00000000000..50ad97be986
--- /dev/null
+++ b/share/btrace/kprofile.bt
@@ -0,0 +1,10 @@
+/*
+ * kprofile.bt	Kernel profiling (stack sampling) at 100Hz.
+ *
+ * To produce a FlameGraph process the output with stackcollapse-bpftrace.pl
+ * and flamegraph.pl found in:
+ *	https://github.com/brendangregg/FlameGraph
+ */
+profile:hz:100 {
+	@[kstack] = count();
+}
diff --git a/share/btrace/runqlat.bt b/share/btrace/runqlat.bt
new file mode 100644
index 00000000000..03a55a62e7e
--- /dev/null
+++ b/share/btrace/runqlat.bt
@@ -0,0 +1,77 @@
+/*
+ * runqlat.bt	Measure run queue latency (aka scheduler latency). OpenBSD.
+ *
+ * This measures the time from enqueue to on-cpu, for the same thread.
+ *
+ * WARNING: This traces scheduler functions, which can incur high overhead.
+ * This is not suitable for 24x7 monitoring.
+ *
+ * Copyright (c) 2014 Brendan Gregg. All rights reserved.
+ * Copyright (c) 2021 Martin Pieuchot. All rights reserved.
+ *
+ * Redistribution and usece in source and binary forusec, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code musect retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form musect reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF usecE, DATA, OR PROFITS; OR BusecINESS INTERRUPTION)
+ * HOWEVER CAusecED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE usecE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * 19-Jun-2014	Brendan Gregg	Created this.
+ * 08-Sep-2021	Martin Pieuchot Ported this to OpenBSD's btrace(8)
+ */
+
+/*
+ * Work around multiple enqueue/dequeue cycles due to priority changes
+ * before executing by registering only the first time a thread is put
+ * on a scheduler queue.
+ */
+tracepoint:sched:enqueue
+/@ts[arg0] == 0/
+{
+	/*
+	 * For the enqueue and dequeue probes, arg0 is the thread ID.
+	 */
+	@ts[arg0] = nsecs
+}
+
+tracepoint:sched:on__cpu
+/@ts[tid]/
+{
+	$usec = (nsecs - @ts[tid]) / 1000;
+	@max_usec[0] = max($usec);
+	@dist_usec = hist($usec);
+	delete(@ts[tid]);
+}
+
+interval:hz:1
+{
+	time("%H:%M:%S  ");
+	printf("Run queue latency (us):\n");
+	print(@dist_usec);
+	printf("Max run queue latency: %d ms\n", @max_usec[0] / 1000);
+	clear(@dist_usec); clear(@max_usec);
+}
+
+END
+{
+	clear(@ts);
+	time("%H:%M:%S  ");
+	printf("Run queue latency (us):\n");
+	print(@dist_usec);
+	printf("Max run queue latency: %d ms\n", @max_usec[0] / 1000);
+	clear(@dist_usec); clear(@max_usec);
+}