From: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
To: "Tan, Jianfeng" <jianfeng.tan@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>,
"Burakov, Anatoly" <anatoly.burakov@intel.com>
Cc: "Richardson, Bruce" <bruce.richardson@intel.com>,
"thomas@monjalon.net" <thomas@monjalon.net>
Subject: Re: [dpdk-dev] [PATCH v2 3/4] eal: add synchronous multi-process communication
Date: Tue, 16 Jan 2018 11:12:47 +0000 [thread overview]
Message-ID: <2601191342CEEE43887BDE71AB9772588627E2D8@irsmsx105.ger.corp.intel.com> (raw)
In-Reply-To: <5733adcf-ef47-2c07-a39c-7eda01add6e0@intel.com>
Hi Jianfeng,
> -----Original Message-----
> From: Tan, Jianfeng
> Sent: Tuesday, January 16, 2018 8:11 AM
> To: Ananyev, Konstantin <konstantin.ananyev@intel.com>; dev@dpdk.org; Burakov, Anatoly <anatoly.burakov@intel.com>
> Cc: Richardson, Bruce <bruce.richardson@intel.com>; thomas@monjalon.net
> Subject: Re: [PATCH v2 3/4] eal: add synchronous multi-process communication
>
> Thank you, Konstantin and Anatoly firstly. Other comments are well
> received and I'll send out a new version.
>
>
> On 1/16/2018 8:00 AM, Ananyev, Konstantin wrote:
> >
> >> We need the synchronous way for multi-process communication,
> >> i.e., blockingly waiting for reply message when we send a request
> >> to the peer process.
> >>
> >> We add two APIs rte_eal_mp_request() and rte_eal_mp_reply() for
> >> such use case. By invoking rte_eal_mp_request(), a request message
> >> is sent out, and then it waits there for a reply message. The
> >> timeout is hard-coded 5 Sec. And the replied message will be copied
> >> in the parameters of this API so that the caller can decide how
> >> to translate those information (including params and fds). Note
> >> if a primary process owns multiple secondary processes, this API
> >> will fail.
> >>
> >> The API rte_eal_mp_reply() is always called by an mp action handler.
> >> Here we add another parameter for rte_eal_mp_t so that the action
> >> handler knows which peer address to reply.
> >>
> >> We use mutex in rte_eal_mp_request() to guarantee that only one
> >> request is on the fly for one pair of processes.
> > You don't need to do things in such strange and restrictive way.
> > Instead you can do something like that:
> > 1) Introduce new struct, list for it and mutex
> > struct sync_request {
> > int reply_received;
> > char dst[PATH_MAX];
> > char reply[...];
> > LIST_ENTRY(sync_request) next;
> > };
> >
> > static struct
> > LIST_HEAD(list, sync_request);
> > pthread_mutex_t lock;
> > pthead_cond_t cond;
> > } sync_requests;
> >
> > 2) then at request() call:
> > Grab sync_requests.lock
> > Check do we already have a pending request for that destination,
> > If yes - the release the lock and returns with error.
> > - allocate and init new sync_request struct, set reply_received=0
> > - do send_msg()
> > -then in a cycle:
> > pthread_cond_timed_wait(&sync_requests.cond, &sync_request.lock, ×pec);
> > - at return from it check if sync_request.reply_received == 1, if not
> > check if timeout expired and either return a failure or go to the start of the cycle.
> >
> > 3) at mp_handler() if REPLY received - grab sync_request.lock,
> > search through sync_requests.list for dst[] ,
> > if found, then set it's reply_received=1, copy the received message into reply
> > and call pthread_cond_braodcast((&sync_requests.cond);
>
> The only benefit I can see is that now the sender can request to
> multiple receivers at the same time. And it makes things more
> complicated. Do we really need this?
The benefit is that one thread is blocked waiting for response,
your mp_handler can still receive and handle other messages.
Plus as you said - other threads can keep sending messages.
Konstantin
>
> Thanks,
> Jianfeng
next prev parent reply other threads:[~2018-01-16 11:12 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-30 18:44 [dpdk-dev] [PATCH 0/3] generic channel for " Jianfeng Tan
2017-11-30 18:44 ` [dpdk-dev] [PATCH 1/3] eal: add " Jianfeng Tan
2017-12-11 11:04 ` Burakov, Anatoly
2017-12-11 16:43 ` Ananyev, Konstantin
2017-11-30 18:44 ` [dpdk-dev] [PATCH 2/3] eal: add synchronous " Jianfeng Tan
2017-12-11 11:39 ` Burakov, Anatoly
2017-12-11 16:49 ` Ananyev, Konstantin
2017-11-30 18:44 ` [dpdk-dev] [PATCH 3/3] vfio: use the generic multi-process channel Jianfeng Tan
2017-12-11 12:01 ` Burakov, Anatoly
2017-12-11 9:59 ` [dpdk-dev] [PATCH 0/3] generic channel for multi-process communication Burakov, Anatoly
2017-12-12 7:34 ` Tan, Jianfeng
2017-12-12 16:18 ` Burakov, Anatoly
2018-01-11 4:07 ` [dpdk-dev] [PATCH v2 0/4] " Jianfeng Tan
2018-01-11 4:07 ` [dpdk-dev] [PATCH v2 1/4] eal: add " Jianfeng Tan
2018-01-13 12:57 ` Burakov, Anatoly
2018-01-15 19:52 ` Ananyev, Konstantin
2018-01-11 4:07 ` [dpdk-dev] [PATCH v2 2/4] eal: add and del secondary processes in the primary Jianfeng Tan
2018-01-13 13:11 ` Burakov, Anatoly
2018-01-15 21:45 ` Ananyev, Konstantin
2018-01-11 4:07 ` [dpdk-dev] [PATCH v2 3/4] eal: add synchronous multi-process communication Jianfeng Tan
2018-01-13 13:41 ` Burakov, Anatoly
2018-01-16 0:00 ` Ananyev, Konstantin
2018-01-16 8:10 ` Tan, Jianfeng
2018-01-16 11:12 ` Ananyev, Konstantin [this message]
2018-01-16 16:47 ` Tan, Jianfeng
2018-01-17 10:50 ` Ananyev, Konstantin
2018-01-17 13:09 ` Tan, Jianfeng
2018-01-17 13:15 ` Tan, Jianfeng
2018-01-17 17:20 ` Ananyev, Konstantin
2018-01-11 4:07 ` [dpdk-dev] [PATCH v2 4/4] vfio: use the generic multi-process channel Jianfeng Tan
2018-01-13 14:03 ` Burakov, Anatoly
2018-03-04 14:57 ` [dpdk-dev] [PATCH v5] vfio: change to use " Jianfeng Tan
2018-03-14 13:27 ` Burakov, Anatoly
2018-03-19 6:53 ` Tan, Jianfeng
2018-03-20 10:33 ` Burakov, Anatoly
2018-03-20 10:56 ` Burakov, Anatoly
2018-03-20 8:50 ` [dpdk-dev] [PATCH v6] " Jianfeng Tan
2018-04-05 14:26 ` Tan, Jianfeng
2018-04-05 14:39 ` Burakov, Anatoly
2018-04-12 23:27 ` Thomas Monjalon
2018-04-12 15:26 ` Burakov, Anatoly
2018-04-15 15:06 ` [dpdk-dev] [PATCH v7] " Jianfeng Tan
2018-04-15 15:10 ` Tan, Jianfeng
2018-04-17 23:04 ` Thomas Monjalon
2018-01-25 4:16 ` [dpdk-dev] [PATCH v3 0/3] generic channel for multi-process communication Jianfeng Tan
2018-01-25 4:16 ` [dpdk-dev] [PATCH v3 1/3] eal: add " Jianfeng Tan
2018-01-25 10:41 ` Thomas Monjalon
2018-01-25 11:27 ` Burakov, Anatoly
2018-01-25 11:34 ` Thomas Monjalon
2018-01-25 12:21 ` Ananyev, Konstantin
2018-01-25 4:16 ` [dpdk-dev] [PATCH v3 2/3] eal: add synchronous " Jianfeng Tan
2018-01-25 12:00 ` Burakov, Anatoly
2018-01-25 12:19 ` Ananyev, Konstantin
2018-01-25 12:25 ` Burakov, Anatoly
2018-01-25 13:00 ` Ananyev, Konstantin
2018-01-25 13:05 ` Burakov, Anatoly
2018-01-25 13:10 ` Burakov, Anatoly
2018-01-25 15:03 ` Ananyev, Konstantin
2018-01-25 16:22 ` Burakov, Anatoly
2018-01-25 17:10 ` Tan, Jianfeng
2018-01-25 18:02 ` Burakov, Anatoly
2018-01-25 12:19 ` Burakov, Anatoly
2018-01-25 12:22 ` Ananyev, Konstantin
2018-01-25 4:16 ` [dpdk-dev] [PATCH v3 3/3] vfio: use the generic multi-process channel Jianfeng Tan
2018-01-25 10:47 ` Thomas Monjalon
2018-01-25 10:52 ` Burakov, Anatoly
2018-01-25 10:57 ` Thomas Monjalon
2018-01-25 12:15 ` Burakov, Anatoly
2018-01-25 19:14 ` [dpdk-dev] [PATCH v4 0/2] generic channel for multi-process communication Jianfeng Tan
2018-01-25 19:14 ` [dpdk-dev] [PATCH v4 1/2] eal: add synchronous " Jianfeng Tan
2018-01-25 19:14 ` [dpdk-dev] [PATCH v4 2/2] vfio: use the generic multi-process channel Jianfeng Tan
2018-01-25 19:15 ` [dpdk-dev] [PATCH v4 0/2] generic channel for multi-process communication Tan, Jianfeng
2018-01-25 19:21 ` [dpdk-dev] [PATCH v5 " Jianfeng Tan
2018-01-25 19:21 ` [dpdk-dev] [PATCH v5 1/2] eal: add " Jianfeng Tan
2018-01-25 19:21 ` [dpdk-dev] [PATCH v5 2/2] eal: add synchronous " Jianfeng Tan
2018-01-25 21:23 ` [dpdk-dev] [PATCH v5 0/2] generic channel for " Thomas Monjalon
2018-01-26 3:41 ` [dpdk-dev] [PATCH v6 " Jianfeng Tan
2018-01-26 3:41 ` [dpdk-dev] [PATCH v6 1/2] eal: add " Jianfeng Tan
2018-01-26 10:25 ` Burakov, Anatoly
2018-01-29 6:37 ` Tan, Jianfeng
2018-01-29 9:37 ` Burakov, Anatoly
2018-01-26 3:41 ` [dpdk-dev] [PATCH v6 2/2] eal: add synchronous " Jianfeng Tan
2018-01-26 10:31 ` Burakov, Anatoly
2018-01-29 23:52 ` [dpdk-dev] [PATCH v6 0/2] generic channel for " Thomas Monjalon
2018-01-30 6:58 ` [dpdk-dev] [PATCH v7 " Jianfeng Tan
2018-01-30 6:58 ` [dpdk-dev] [PATCH v7 1/2] eal: add " Jianfeng Tan
2018-01-30 6:58 ` [dpdk-dev] [PATCH v7 2/2] eal: add synchronous " Jianfeng Tan
2018-01-30 14:46 ` [dpdk-dev] [PATCH v7 0/2] generic channel for " Thomas Monjalon
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