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Subject: Re: [OMPI devel] [OMPI svn] svn:open-mpi r31376 - trunk/orte/mca/oob/tcp
From: George Bosilca (bosilca_at_[hidden])
Date: 2014-04-13 19:42:36


Inter-process communications are better handled via pipes and sockets than opening /dev/null. More generic and it does not depend on any particularities of the /dev/null file system implementation.

  George.

On Apr 13, 2014, at 19:26 , Ralph Castain <rhc_at_[hidden]> wrote:

> ??? How is that any different/better than what was done?
>
>
> On Apr 13, 2014, at 4:23 PM, George Bosilca <bosilca_at_[hidden]> wrote:
>
>> Isn’t a socket or a pipe the right way to address this issue?
>>
>> George.
>>
>> On Apr 12, 2014, at 11:01 , svn-commit-mailer_at_[hidden] wrote:
>>
>>> Author: rhc (Ralph Castain)
>>> Date: 2014-04-12 11:01:24 EDT (Sat, 12 Apr 2014)
>>> New Revision: 31376
>>> URL: https://svn.open-mpi.org/trac/ompi/changeset/31376
>>>
>>> Log:
>>> Ensure we properly terminate the listening thread prior to exiting, but do so in a way that doesn't make us wait for select to timeout.
>>>
>>> Refs #4510
>>>
>>> Text files modified:
>>> trunk/orte/mca/oob/tcp/oob_tcp_component.c | 9 ++++++---
>>> trunk/orte/mca/oob/tcp/oob_tcp_component.h | 2 ++
>>> trunk/orte/mca/oob/tcp/oob_tcp_listener.c | 17 ++++++++++++-----
>>> 3 files changed, 20 insertions(+), 8 deletions(-)
>>>
>>> Modified: trunk/orte/mca/oob/tcp/oob_tcp_component.c
>>> ==============================================================================
>>> --- trunk/orte/mca/oob/tcp/oob_tcp_component.c Sat Apr 12 10:43:20 2014 (r31375)
>>> +++ trunk/orte/mca/oob/tcp/oob_tcp_component.c 2014-04-12 11:01:24 EDT (Sat, 12 Apr 2014) (r31376)
>>> @@ -140,8 +140,8 @@
>>> if (ORTE_PROC_IS_HNP) {
>>> OBJ_CONSTRUCT(&mca_oob_tcp_component.listen_thread, opal_thread_t);
>>> mca_oob_tcp_component.listen_thread_active = false;
>>> - mca_oob_tcp_component.listen_thread_tv.tv_sec = 0;
>>> - mca_oob_tcp_component.listen_thread_tv.tv_usec = 300000;
>>> + mca_oob_tcp_component.listen_thread_tv.tv_sec = 3600;
>>> + mca_oob_tcp_component.listen_thread_tv.tv_usec = 0;
>>> }
>>> mca_oob_tcp_component.addr_count = 0;
>>> OBJ_CONSTRUCT(&mca_oob_tcp_component.modules, opal_pointer_array_t);
>>> @@ -659,7 +659,10 @@
>>> ORTE_NAME_PRINT(ORTE_PROC_MY_NAME));
>>>
>>> if (ORTE_PROC_IS_HNP && mca_oob_tcp_component.listen_thread_active) {
>>> - mca_oob_tcp_component.listen_thread_active = 0;
>>> + mca_oob_tcp_component.listen_thread_active = false;
>>> + /* tell the thread to exit */
>>> + write(mca_oob_tcp_component.stop_thread, &i, sizeof(int));
>>> + opal_thread_join(&mca_oob_tcp_component.listen_thread, NULL);
>>> }
>>>
>>> while (NULL != (item = opal_list_remove_first(&mca_oob_tcp_component.listeners))) {
>>>
>>> Modified: trunk/orte/mca/oob/tcp/oob_tcp_component.h
>>> ==============================================================================
>>> --- trunk/orte/mca/oob/tcp/oob_tcp_component.h Sat Apr 12 10:43:20 2014 (r31375)
>>> +++ trunk/orte/mca/oob/tcp/oob_tcp_component.h 2014-04-12 11:01:24 EDT (Sat, 12 Apr 2014) (r31376)
>>> @@ -12,6 +12,7 @@
>>> * Copyright (c) 2006-2013 Los Alamos National Security, LLC.
>>> * All rights reserved.
>>> * Copyright (c) 2010-2011 Cisco Systems, Inc. All rights reserved.
>>> + * Copyright (c) 2014 Intel, Inc. All rights reserved
>>> * $COPYRIGHT$
>>> *
>>> * Additional copyrights may follow
>>> @@ -77,6 +78,7 @@
>>> opal_thread_t listen_thread; /**< handle to the listening thread */
>>> bool listen_thread_active;
>>> struct timeval listen_thread_tv; /**< Timeout when using listen thread */
>>> + int stop_thread; /**< file descriptor used to exit the listen thread */
>>>
>>> /* peers available via this transport - the index is the process name,
>>> * and the pointer returned is the pointer to the last module that
>>>
>>> Modified: trunk/orte/mca/oob/tcp/oob_tcp_listener.c
>>> ==============================================================================
>>> --- trunk/orte/mca/oob/tcp/oob_tcp_listener.c Sat Apr 12 10:43:20 2014 (r31375)
>>> +++ trunk/orte/mca/oob/tcp/oob_tcp_listener.c 2014-04-12 11:01:24 EDT (Sat, 12 Apr 2014) (r31376)
>>> @@ -121,11 +121,11 @@
>>> }
>>> #endif
>>>
>>> - /* if I am the HNP, create a separate event base for the
>>> - * listening thread so we can harvest connection requests
>>> - * as rapidly as possible
>>> + /* if I am the HNP, start a listening thread so we can
>>> + * harvest connection requests as rapidly as possible
>>> */
>>> if (ORTE_PROC_IS_HNP) {
>>> + mca_oob_tcp_component.stop_thread = open("/dev/null", O_RDWR);
>>> mca_oob_tcp_component.listen_thread_active = true;
>>> mca_oob_tcp_component.listen_thread.t_run = listen_thread;
>>> mca_oob_tcp_component.listen_thread.t_arg = NULL;
>>> @@ -641,15 +641,22 @@
>>> FD_SET(listener->sd, &readfds);
>>> max = (listener->sd > max) ? listener->sd : max;
>>> }
>>> + /* add the stop_thread fd */
>>> + FD_SET(mca_oob_tcp_component.stop_thread, &readfds);
>>> + max = (mca_oob_tcp_component.stop_thread > max) ? mca_oob_tcp_component.stop_thread : max;
>>> +
>>> /* set timeout interval */
>>> timeout.tv_sec = mca_oob_tcp_component.listen_thread_tv.tv_sec;
>>> timeout.tv_usec = mca_oob_tcp_component.listen_thread_tv.tv_usec;
>>>
>>> - /* Block in a select for a short (10ms) amount of time to
>>> - * avoid hammering the cpu. If a connection
>>> + /* Block in a select to avoid hammering the cpu. If a connection
>>> * comes in, we'll get woken up right away.
>>> */
>>> rc = select(max + 1, &readfds, NULL, NULL, &timeout);
>>> + if (!mca_oob_tcp_component.listen_thread_active) {
>>> + /* we've been asked to terminate */
>>> + return NULL;
>>> + }
>>> if (rc < 0) {
>>> if (EAGAIN != opal_socket_errno && EINTR != opal_socket_errno) {
>>> perror("select");
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>>
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