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From: "Liang, Cunming" <cunming.liang@intel.com>
To: Stephen Hemminger <stephen@networkplumber.org>,
	"Richardson, Bruce" <bruce.richardson@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [RFC PATCH 0/7] support multi-phtread per lcore
Date: Tue, 23 Dec 2014 09:51:58 +0000	[thread overview]
Message-ID: <D0158A423229094DA7ABF71CF2FA0DA31188F9AD@shsmsx102.ccr.corp.intel.com> (raw)
In-Reply-To: <20141222102852.7e6d5e81@urahara>



> -----Original Message-----
> From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> Sent: Tuesday, December 23, 2014 2:29 AM
> To: Richardson, Bruce
> Cc: Liang, Cunming; dev@dpdk.org
> Subject: Re: [dpdk-dev] [RFC PATCH 0/7] support multi-phtread per lcore
> 
> On Mon, 22 Dec 2014 09:46:03 +0000
> Bruce Richardson <bruce.richardson@intel.com> wrote:
> 
> > On Mon, Dec 22, 2014 at 01:51:27AM +0000, Liang, Cunming wrote:
> > > ...
> > > > I'm conflicted on this one. However, I think far more applications would be
> > > > broken
> > > > to start having to use thread_id in place of an lcore_id than would be
> broken
> > > > by having the lcore_id no longer actually correspond to a core.
> > > > I'm actually struggling to come up with a large number of scenarios where
> it's
> > > > important to an app to determine the cpu it's running on, compared to the
> large
> > > > number of cases where you need to have a data-structure per thread. In
> DPDK
> > > > libs
> > > > alone, you see this assumption that lcore_id == thread_id a large number
> of
> > > > times.
> > > >
> > > > Despite the slight logical inconsistency, I think it's better to avoid
> introducing
> > > > a thread-id and continue having lcore_id representing a unique thread.
> > > >
> > > > /Bruce
> > >
> > > Ok, I understand it.
> > > I list the implicit meaning if using lcore_id representing the unique thread.
> > > 1). When lcore_id less than RTE_MAX_LCORE, it still represents the logical
> core id.
> > > 2). When lcore_id large equal than RTE_MAX_LCORE, it represents an unique
> id for thread.
> > > 3). Most of APIs(except rte_lcore_id()) in rte_lcore.h suggest to be used only
> in CASE 1)
> > > 4). rte_lcore_id() can be used in CASE 2), but the return value no matter
> represent a logical core id.
> > >
> > > If most of us feel it's acceptable, I'll prepare for the RFC v2 base on this
> conclusion.
> > >
> > > /Cunming
> >
> > Sorry, I don't like that suggestion either, as having lcore_id values greater
> > than RTE_MAX_LCORE is terrible, as how will people know how to dimension
> arrays
> > to be indexes by lcore id? Given the choice, if we are not going to just use
> > lcore_id as a generic thread id, which is always between 0 and
> RTE_MAX_LCORE
> > we can look to define a new thread_id variable to hold that. However, it should
> > have a bounded range.
> > From an ease-of-porting perspective, I still think that the simplest option is to
> > use the existing lcore_id and accept the fact that it's now a thread id rather
> > than an actual physical lcore. Question is, is would that cause us lots of issues
> > in the future?
> >
> > /Bruce
> 
> The current rte_lcore_id() has different meaning the thread. Your proposal will
> break code that uses lcore_id to do per-cpu statistics and the lcore_config
> code in the samples.
> q
[Liang, Cunming] +1. 

  parent reply	other threads:[~2014-12-23  9:52 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-11  2:04 Cunming Liang
2014-12-11  2:04 ` [dpdk-dev] [RFC PATCH 1/7] eal: add linear thread id as pthread-local variable Cunming Liang
2014-12-16  7:00   ` Qiu, Michael
2014-12-22 19:02   ` Ananyev, Konstantin
2014-12-23  9:56     ` Liang, Cunming
2014-12-11  2:04 ` [dpdk-dev] [RFC PATCH 2/7] mempool: use linear-tid as mempool cache index Cunming Liang
2014-12-11  2:04 ` [dpdk-dev] [RFC PATCH 3/7] ring: use linear-tid as ring debug stats index Cunming Liang
2014-12-11  2:04 ` [dpdk-dev] [RFC PATCH 4/7] eal: add simple API for multi-pthread Cunming Liang
2014-12-11  2:04 ` [dpdk-dev] [RFC PATCH 5/7] testpmd: support multi-pthread mode Cunming Liang
2014-12-11  2:04 ` [dpdk-dev] [RFC PATCH 6/7] sample: add new sample for multi-pthread Cunming Liang
2014-12-11  2:04 ` [dpdk-dev] [RFC PATCH 7/7] eal: macro for cpuset w/ or w/o CPU_ALLOC Cunming Liang
2014-12-11  2:54 ` [dpdk-dev] [RFC PATCH 0/7] support multi-phtread per lcore Jayakumar, Muthurajan
2014-12-11  9:56 ` Walukiewicz, Miroslaw
2014-12-12  5:44   ` Liang, Cunming
2014-12-15 11:10     ` Walukiewicz, Miroslaw
2014-12-15 11:53       ` Liang, Cunming
2014-12-18 12:20         ` Walukiewicz, Miroslaw
2014-12-18 14:32           ` Bruce Richardson
2014-12-18 15:11             ` Olivier MATZ
2014-12-18 16:04               ` Bruce Richardson
2014-12-18 16:15           ` Stephen Hemminger
2014-12-19  1:28           ` Liang, Cunming
2014-12-19 10:03             ` Bruce Richardson
2014-12-22  1:51               ` Liang, Cunming
2014-12-22  9:46                 ` Bruce Richardson
2014-12-22 10:01                   ` Walukiewicz, Miroslaw
2014-12-23  9:45                     ` Liang, Cunming
2014-12-22 18:28                   ` Stephen Hemminger
2014-12-23  9:19                     ` Walukiewicz, Miroslaw
2014-12-23  9:23                       ` Bruce Richardson
2014-12-23  9:51                     ` Liang, Cunming [this message]
2015-01-08 17:05                       ` Ananyev, Konstantin
2015-01-08 17:23                         ` Richardson, Bruce
2015-01-09  9:51                           ` Liang, Cunming
2015-01-09  9:40                         ` Liang, Cunming
2015-01-09 11:52                           ` Ananyev, Konstantin
2015-01-09  9:45                         ` Liang, Cunming

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