From: Nir Soffer <nsoffer@redhat.com>
To: systemtap@sourceware.org
Subject: [PATCH] Add traceaio example
Date: Wed, 22 Sep 2021 18:24:40 +0300 [thread overview]
Message-ID: <20210922152440.480527-1-nsoffer@redhat.com> (raw)
Show how to trace arguments to io_submit. This is useful to debug EINVAL
errors, for example when number of iovecs exceeds limits.
Signed-off-by: Nir Soffer <nsoffer@redhat.com>
---
testsuite/systemtap.examples/io/traceaio.meta | 13 ++++++
testsuite/systemtap.examples/io/traceaio.stp | 43 ++++++++++++++++++
testsuite/systemtap.examples/io/traceaio.txt | 44 +++++++++++++++++++
3 files changed, 100 insertions(+)
create mode 100644 testsuite/systemtap.examples/io/traceaio.meta
create mode 100755 testsuite/systemtap.examples/io/traceaio.stp
create mode 100644 testsuite/systemtap.examples/io/traceaio.txt
diff --git a/testsuite/systemtap.examples/io/traceaio.meta b/testsuite/systemtap.examples/io/traceaio.meta
new file mode 100644
index 000000000..ea120f9be
--- /dev/null
+++ b/testsuite/systemtap.examples/io/traceaio.meta
@@ -0,0 +1,13 @@
+title: Trace calls to io_submit
+name: traceaio.stp
+version: 1.0
+author: Nir Soffer
+keywords: io
+subsystem: io
+status: production
+exit: user-controlled
+output: trace
+scope: process
+description: Trace calls to io_submit, logging iocbs and iovecs.
+test_check: stap -p4 traceaio.stp -x 1
+test_installcheck: stap traceaio.stp -x 1 -T 1
diff --git a/testsuite/systemtap.examples/io/traceaio.stp b/testsuite/systemtap.examples/io/traceaio.stp
new file mode 100755
index 000000000..126ea9c3c
--- /dev/null
+++ b/testsuite/systemtap.examples/io/traceaio.stp
@@ -0,0 +1,43 @@
+#! /usr/bin/env stap
+#
+# Copyright (C) 2021 Red Hat, Inc.
+# Written by Nir Soffer <nsoffer@redhat.com>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+#
+
+probe begin {
+ println("Tracing started");
+}
+
+probe syscall.io_submit
+{
+ if (pid() == target()) {
+ printf("[%s] io_submit(%s)\n", thread_indent(0), argstr);
+
+ for (i = 0; i < nr; i++) {
+ iocbp = user_uint64(iocbpp_uaddr + i * 8)
+ fd = user_uint32(&@cast(iocbp, "iocb", "kernel")->aio_fildes)
+ opcode = user_uint16(&@cast(iocbp, "iocb", "kernel")->aio_lio_opcode)
+ offset = user_int64(&@cast(iocbp, "iocb", "kernel")->aio_offset)
+ nbytes = user_uint64(&@cast(iocbp, "iocb", "kernel")->aio_nbytes)
+ buf = user_uint64(&@cast(iocbp, "iocb", "kernel")->aio_buf)
+ printf(" iocb[%4d]=%p, fd=%d, opcode=%d, offset=%d, nbytes=%d, buf=%p\n",
+ i, iocbp, fd, opcode, offset, nbytes, buf)
+
+ for (j = 0; j < nbytes; j++) {
+ iovecp = &@cast(buf, "iovec", "kernel")[j]
+ base = user_uint64(&@cast(iovecp, "iovec", "kernel")->iov_base)
+ len = user_uint32(&@cast(iovecp, "iovec", "kernel")->iov_len)
+ printf(" iovec[%4d]=%p, base=%p, len=%d\n",
+ j, iovecp, base, len)
+ }
+ }
+ }
+}
+
+probe end {
+ println("Tracing stopped");
+}
diff --git a/testsuite/systemtap.examples/io/traceaio.txt b/testsuite/systemtap.examples/io/traceaio.txt
new file mode 100644
index 000000000..1d90dc592
--- /dev/null
+++ b/testsuite/systemtap.examples/io/traceaio.txt
@@ -0,0 +1,44 @@
+traceaio.stp - Trace io_submit calls
+
+ Trace calls to io_submit(), logging iocbs and iovecs. When processing calls
+ with large number of iocbs and iovecs, you may need to increase MAXACTION.
+
+# stap -D MAXACTION=2000 traceaio.stp -x {pid}
+Tracing started
+[ 0 IO iothread1(21364):] io_submit(140719456722944, 1, 0x7ffbcf8b2410)
+ iocb[ 0]=0x7ffb1d9d98c0, fd=15, opcode=8, offset=0, nbytes=1, buf=0x7ffbc801b6a8
+ iovec[ 0]=0x7ffbc801b6a8, base=0x7ffb4f9dc000, len=4096
+[ 0 IO iothread1(21364):] io_submit(140719456722944, 1, 0x7ffbcf8b2410)
+ iocb[ 0]=0x7ffb1d9d9920, fd=15, opcode=7, offset=0, nbytes=1, buf=0x7ffbc801b688
+ iovec[ 0]=0x7ffbc801b688, base=0x7ffbb3d11000, len=4096
+[ 0 IO iothread1(21364):] io_submit(140719456722944, 4, 0x7ffbcf8b2410)
+ iocb[ 0]=0x7ffb1d9d9920, fd=15, opcode=7, offset=8192, nbytes=1, buf=0x7ffbc801b688
+ iovec[ 0]=0x7ffbc801b688, base=0x7ffb9d82f000, len=4096
+ iocb[ 1]=0x7ffb251dc920, fd=15, opcode=7, offset=20480, nbytes=2, buf=0x7ffbc80315f0
+ iovec[ 0]=0x7ffbc80315f0, base=0x7ffbb3f69000, len=4096
+ iovec[ 1]=0x7ffbc8031600, base=0x7ffb7dc48000, len=4096
+ iocb[ 2]=0x7ffb19999920, fd=15, opcode=7, offset=36864, nbytes=6, buf=0x7ffbc8025320
+ iovec[ 0]=0x7ffbc8025320, base=0x7ffb4f676000, len=4096
+ iovec[ 1]=0x7ffbc8025330, base=0x7ffbb6f75000, len=4096
+ iovec[ 2]=0x7ffbc8025340, base=0x7ffb9ddab000, len=4096
+ iovec[ 3]=0x7ffbc8025350, base=0x7ffbbab7d000, len=4096
+ iovec[ 4]=0x7ffbc8025360, base=0x7ffb7c3fb000, len=4096
+ iovec[ 5]=0x7ffbc8025370, base=0x7ffb7cff5000, len=4096
+ iocb[ 3]=0x7ffb16f6f920, fd=15, opcode=7, offset=69632, nbytes=15, buf=0x7ffbc80662b8
+ iovec[ 0]=0x7ffbc80662b8, base=0x7ffbb3f44000, len=4096
+ iovec[ 1]=0x7ffbc80662c8, base=0x7ffbb85cd000, len=4096
+ iovec[ 2]=0x7ffbc80662d8, base=0x7ffbb81de000, len=4096
+ iovec[ 3]=0x7ffbc80662e8, base=0x7ffbba3b7000, len=4096
+ iovec[ 4]=0x7ffbc80662f8, base=0x7ffb7daf3000, len=4096
+ iovec[ 5]=0x7ffbc8066308, base=0x7ffbb1ec3000, len=4096
+ iovec[ 6]=0x7ffbc8066318, base=0x7ffbb1ece000, len=4096
+ iovec[ 7]=0x7ffbc8066328, base=0x7ffb7cff7000, len=4096
+ iovec[ 8]=0x7ffbc8066338, base=0x7ffb7cd60000, len=4096
+ iovec[ 9]=0x7ffbc8066348, base=0x7ffbba865000, len=4096
+ iovec[ 10]=0x7ffbc8066358, base=0x7ffbb80cc000, len=4096
+ iovec[ 11]=0x7ffbc8066368, base=0x7ffbb826c000, len=4096
+ iovec[ 12]=0x7ffbc8066378, base=0x7ffbbaa19000, len=4096
+ iovec[ 13]=0x7ffbc8066388, base=0x7ffbb8230000, len=4096
+ iovec[ 14]=0x7ffbc8066398, base=0x7ffbb6ed0000, len=4096
+...
+^CTracing stopped
--
2.31.1
next reply other threads:[~2021-09-22 15:24 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-22 15:24 Nir Soffer [this message]
-- strict thread matches above, loose matches on Subject: below --
2021-09-22 14:45 Nir Soffer
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