[lttng-dev] [PATCH lttng-ust] Add trace instrumentation for some pthread functions.
Mathieu Desnoyers
mathieu.desnoyers at efficios.com
Tue Aug 6 21:32:00 EDT 2013
* Stefan Seefeld (stefan at seefeld.name) wrote:
> On 08/02/2013 09:28 PM, Mathieu Desnoyers wrote:
> > Jeremie is right: incorrect coding style makes the review process harder
> > for us. Once the coding style is right, we can do the functional review
> > of the patch more efficiently.
> >
> > Please resubmit after coding style fixes.
>
> See attached.
Thanks,
Please beware that we're not pulling new features during the -rc cycle.
When the patch is deemed ready, it will be good to keep it around for
submission after 2.3-final is released.
comments inlined below,
>
> Stefan
>
>
> --
>
> ...ich hab' noch einen Koffer in Berlin...
>
> From cc39cdfbfca6d13121270eb9da3aed97be65586c Mon Sep 17 00:00:00 2001
> From: Stefan Seefeld <stefan_seefeld at mentor.com>
> Date: Wed, 31 Jul 2013 16:35:31 -0400
> Subject: [PATCH] Add tracing instrumentation for pthread mutex lock functions.
>
> Signed-off-by: Stefan Seefeld <stefan_seefeld at mentor.com>
> ---
> liblttng-ust-libc-wrapper/Makefile.am | 12 +++-
> liblttng-ust-libc-wrapper/lttng-ust-pthread.c | 91 +++++++++++++++++++++++++++
> liblttng-ust-libc-wrapper/ust_pthread.h | 76 ++++++++++++++++++++++
> 3 files changed, 178 insertions(+), 1 deletion(-)
> create mode 100644 liblttng-ust-libc-wrapper/lttng-ust-pthread.c
> create mode 100644 liblttng-ust-libc-wrapper/ust_pthread.h
>
> diff --git a/liblttng-ust-libc-wrapper/Makefile.am b/liblttng-ust-libc-wrapper/Makefile.am
> index 4fdcedb..d402d53 100644
> --- a/liblttng-ust-libc-wrapper/Makefile.am
> +++ b/liblttng-ust-libc-wrapper/Makefile.am
> @@ -1,7 +1,8 @@
> AM_CPPFLAGS = -I$(top_srcdir)/include -I$(top_builddir)/include
> AM_CFLAGS = -fno-strict-aliasing
>
> -lib_LTLIBRARIES = liblttng-ust-libc-wrapper.la
> +lib_LTLIBRARIES = liblttng-ust-libc-wrapper.la \
> + liblttng-ust-pthread-wrapper.la
> liblttng_ust_libc_wrapper_la_SOURCES = \
> lttng-ust-malloc.c \
> ust_libc.h
> @@ -9,11 +10,20 @@ liblttng_ust_libc_wrapper_la_LIBADD = \
> -L$(top_builddir)/liblttng-ust/.libs \
> -llttng-ust
>
> +liblttng_ust_pthread_wrapper_la_SOURCES = \
> + lttng-ust-pthread.c \
> + ust_pthread.h
> +liblttng_ust_pthread_wrapper_la_LIBADD = \
> + -L$(top_builddir)/liblttng-ust/.libs \
> + -llttng-ust
> +
> if LTTNG_UST_BUILD_WITH_LIBDL
> liblttng_ust_libc_wrapper_la_LIBADD += -ldl
> +liblttng_ust_pthread_wrapper_la_LIBADD += -ldl
> endif
> if LTTNG_UST_BUILD_WITH_LIBC_DL
> liblttng_ust_libc_wrapper_la_LIBADD += -lc
> +liblttng_ust_pthread_wrapper_la_LIBADD += -lc
> endif
>
> noinst_SCRIPTS = run
> diff --git a/liblttng-ust-libc-wrapper/lttng-ust-pthread.c b/liblttng-ust-libc-wrapper/lttng-ust-pthread.c
> new file mode 100644
> index 0000000..98ce9bf
> --- /dev/null
> +++ b/liblttng-ust-libc-wrapper/lttng-ust-pthread.c
> @@ -0,0 +1,91 @@
> +/*
> + * Copyright (C) 2013 Mentor Graphics
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> + */
> +
> +#define _GNU_SOURCE
> +#include <dlfcn.h>
> +#include <pthread.h>
> +
> +#define TRACEPOINT_DEFINE
> +#define TRACEPOINT_CREATE_PROBES
> +#include "ust_pthread.h"
> +
> +static __thread int thread_in_trace;
> +
> +int pthread_mutex_lock(pthread_mutex_t *mutex)
> +{
> + static int (*mutex_lock)(pthread_mutex_t *);
please add newline.
> + if (!mutex_lock) {
> + mutex_lock = dlsym(RTLD_NEXT, "pthread_mutex_lock");
> + if (!mutex_lock) {
> + fprintf(stderr, "unable to initialize pthread wrapper library.\n");
is it possible that fprintf calls pthread_mutex_lock at some point ? If
so, this should be surrounded within thread_in_trace check.
> + return EINVAL;
> + }
> + }
> + if (!thread_in_trace) {
> + thread_in_trace = 1;
> + tracepoint(ust_pthread, pthread_mutex_lock_req, mutex);
> + int retval = mutex_lock(mutex);
please avoid declaring a variable with code. Always do so at the
beginning of a block.
> + tracepoint(ust_pthread, pthread_mutex_lock_acq, mutex, retval);
> + thread_in_trace = 0;
> + return retval;
> + } else {
> + return mutex_lock(mutex);
> + }
I'd prefer something like:
if (thread_in_trace) {
return mutex_lock(mutex);
}
thread_in_trace = 1;
tracepoint(ust_pthread, pthread_mutex_lock_req, mutex);
retval = mutex_lock(mutex);
tracepoint(ust_pthread, pthread_mutex_lock_acq, mutex, retval);
thread_in_trace = 0;
return retval;
so we can remove a level of indentation by only putting the
special-cases at the beginning in the if (with a return within the true
block).
Similar comments apply throughout this patch.
> +}
> +
> +int pthread_mutex_trylock(pthread_mutex_t *mutex)
> +{
> + static int (*mutex_trylock)(pthread_mutex_t *);
> + if (!mutex_trylock) {
> + mutex_trylock = dlsym(RTLD_NEXT, "pthread_mutex_trylock");
> + if (!mutex_trylock) {
> + fprintf(stderr, "unable to initialize pthread wrapper library.\n");
> + return EINVAL;
> + }
> + }
> + if (!thread_in_trace) {
> + thread_in_trace = 1;
> + int retval = mutex_trylock(mutex);
> + tracepoint(ust_pthread, pthread_mutex_trylock, mutex, retval);
> + thread_in_trace = 0;
> + return retval;
> + } else {
> + return mutex_trylock(mutex);
> + }
> +}
> +
> +int pthread_mutex_unlock(pthread_mutex_t *mutex)
> +{
> + static int (*mutex_unlock)(pthread_mutex_t *);
> + if (!mutex_unlock) {
> + mutex_unlock = dlsym(RTLD_NEXT, "pthread_mutex_unlock");
> + if (!mutex_unlock) {
> + fprintf(stderr, "unable to initialize pthread wrapper library.\n");
> + return EINVAL;
> + }
> + }
> + if (!thread_in_trace) {
> + thread_in_trace = 1;
> + int retval = mutex_unlock(mutex);
> + tracepoint(ust_pthread, pthread_mutex_unlock, mutex, retval);
> + thread_in_trace = 0;
> + return retval;
> + } else {
> + return mutex_unlock(mutex);
> + }
> +}
> diff --git a/liblttng-ust-libc-wrapper/ust_pthread.h b/liblttng-ust-libc-wrapper/ust_pthread.h
> new file mode 100644
> index 0000000..86275b7
> --- /dev/null
> +++ b/liblttng-ust-libc-wrapper/ust_pthread.h
> @@ -0,0 +1,76 @@
> +#undef TRACEPOINT_PROVIDER
> +#define TRACEPOINT_PROVIDER ust_pthread
> +
> +#if !defined(_TRACEPOINT_UST_PTHREAD_H) || defined(TRACEPOINT_HEADER_MULTI_READ)
> +#define _TRACEPOINT_UST_PTHREAD_H
> +
> +#ifdef __cplusplus
> +extern "C" {
> +#endif
> +
> +/*
> + * Copyright (C) 2013 Mentor Graphics
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this software and associated documentation files (the "Software"), to deal
> + * in the Software without restriction, including without limitation the rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
> + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
> + * SOFTWARE.
> + */
> +
> +#include <lttng/tracepoint.h>
> +
> +TRACEPOINT_EVENT(ust_pthread, pthread_mutex_lock_req,
> + TP_ARGS(pthread_mutex_t *, mutex),
> + TP_FIELDS(
> + ctf_integer_hex(unsigned long, mutex, (unsigned long) mutex)
I'm curious (and I honestly don't remember): does it work if we put
"void *" as type rather than "unsigned long" here ?
Thanks,
Mathieu
> + )
> +)
> +
> +TRACEPOINT_EVENT(ust_pthread, pthread_mutex_lock_acq,
> + TP_ARGS(pthread_mutex_t *, mutex, int, status),
> + TP_FIELDS(
> + ctf_integer_hex(unsigned long, mutex, (unsigned long) mutex)
> + ctf_integer(int, status, status)
> + )
> +)
> +
> +TRACEPOINT_EVENT(ust_pthread, pthread_mutex_trylock,
> + TP_ARGS(pthread_mutex_t *, mutex, int, status),
> + TP_FIELDS(
> + ctf_integer_hex(unsigned long, mutex, (unsigned long) mutex)
> + ctf_integer(int, status, status)
> + )
> +)
> +
> +TRACEPOINT_EVENT(ust_pthread, pthread_mutex_unlock,
> + TP_ARGS(pthread_mutex_t *, mutex, int, status),
> + TP_FIELDS(
> + ctf_integer_hex(unsigned long, mutex, (unsigned long) mutex)
> + ctf_integer(int, status, status)
> + )
> +)
> +
> +#endif /* _TRACEPOINT_UST_PTHREAD_H */
> +
> +#undef TRACEPOINT_INCLUDE
> +#define TRACEPOINT_INCLUDE "./ust_pthread.h"
> +
> +/* This part must be outside ifdef protection */
> +#include <lttng/tracepoint-event.h>
> +
> +#ifdef __cplusplus
> +}
> +#endif
> --
> 1.8.3.1
>
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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