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From: "Zhang, Helin" <helin.zhang@intel.com>
To: Thomas Monjalon <thomas.monjalon@6wind.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v5 1/5] i40e: Use constant random hash keys
Date: Tue, 11 Nov 2014 03:30:25 +0000	[thread overview]
Message-ID: <F35DEAC7BCE34641BA9FAC6BCA4A12E70A7BB803@SHSMSX104.ccr.corp.intel.com> (raw)
In-Reply-To: <1526321.WRfZaPjy3u@xps13>



> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> Sent: Monday, November 3, 2014 4:59 PM
> To: Zhang, Helin
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v5 1/5] i40e: Use constant random hash keys
> 
> 2014-11-03 08:18, Zhang, Helin:
> > From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> > > The title is a bit surprising:
> > > - it should be about RSS
> >
> > RSS makes use of hash function to route received packets, though hash
> > function can be used for other cases, e.g. Flow director.
> 
> Yes but this patch is only changing rss_key_default so I guess it's only related to
> RSS, right?
Yes, it is currently for rss only.

> 
> > > - a constant cannot be really random ;)
The comments could be re-worded.

> >
> > The hash keys are generated by libc random function.
> > It is preparatory to avoid calling random function for each port.
> 
> Here, you remove the call to rte_rand by a constant value.
No need to calculate it every time, like what Linux i40e driver does.

> 
> > > 2014-10-21 11:14, Helin Zhang:
> > > > To be simpler, and remove the race condition, it uses prepared
> > > > constant random hash keys to replace runtime generating the hash keys.
> > >
> > > Could you explain what is the role of rss_key_default?
> >
> > Hash function needs to be configured with keys, before end users
> > configured them with specific keys, we need to provide a default keys
> > which is generated by libc random function.
> > The random keys can get the hash function to route the received
> > packets to all the queues well-proportioned.

Regards,
Helin

  parent reply	other threads:[~2014-11-11  3:21 UTC|newest]

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-30  6:20 [dpdk-dev] [PATCH v3 0/7] Support configuring hash functions Helin Zhang
2014-09-30  6:20 ` [dpdk-dev] [PATCH v3 1/7] ethdev: add more annotations Helin Zhang
2014-10-13  6:12   ` [dpdk-dev] [PATCH v4 0/7] Support configuring hash functions Helin Zhang
2014-10-13  6:12     ` [dpdk-dev] [PATCH v4 1/7] ethdev: add more annotations Helin Zhang
2014-10-13  6:12     ` [dpdk-dev] [PATCH v4 2/7] ethdev: add interfaces and relevant for filter control Helin Zhang
2014-10-13  6:12     ` [dpdk-dev] [PATCH v4 3/7] ethdev: add structures and enum for hash " Helin Zhang
2014-10-13  6:12     ` [dpdk-dev] [PATCH v4 4/7] i40e: add hash filter control implementation Helin Zhang
2014-10-13 10:23       ` Chilikin, Andrey
2014-10-14  0:42         ` Zhang, Helin
2014-10-13  6:12     ` [dpdk-dev] [PATCH v4 5/7] i40e: add hardware initialization Helin Zhang
2014-10-13  6:12     ` [dpdk-dev] [PATCH v4 6/7] i40e: Use constant random hash keys Helin Zhang
2014-10-13  6:12     ` [dpdk-dev] [PATCH v4 7/7] app/testpmd: add commands to support hash filter control Helin Zhang
2014-10-13 12:27     ` [dpdk-dev] [PATCH v4 0/7] Support configuring hash functions Zhan, Zhaochen
2014-10-14  3:32     ` Wu, Jingjing
2014-10-21  3:14     ` [dpdk-dev] [PATCH v5 0/5] " Helin Zhang
2014-10-21  3:14       ` [dpdk-dev] [PATCH v5 1/5] i40e: Use constant random hash keys Helin Zhang
2014-11-03  7:49         ` Thomas Monjalon
2014-11-03  8:18           ` Zhang, Helin
2014-11-03  8:59             ` Thomas Monjalon
2014-11-06  7:52               ` Zhang, Helin
2014-11-11  3:30               ` Zhang, Helin [this message]
2014-10-21  3:14       ` [dpdk-dev] [PATCH v5 2/5] ethdev: add enum type and relevant structures for hash filter control Helin Zhang
2014-11-03  7:57         ` Thomas Monjalon
2014-11-06  3:41           ` Zhang, Helin
2014-11-06  8:43             ` Thomas Monjalon
2014-11-06  8:54               ` Zhang, Helin
2014-11-11  3:27           ` Zhang, Helin
2014-11-11  6:46           ` Zhang, Helin
2014-11-11 21:08             ` Thomas Monjalon
2014-11-12  5:52               ` Zhang, Helin
2014-11-12  9:30                 ` Thomas Monjalon
2014-11-12 14:22                   ` Zhang, Helin
2014-10-21  3:14       ` [dpdk-dev] [PATCH v5 3/5] i40e: add hash filter control implementation Helin Zhang
2014-10-21  3:14       ` [dpdk-dev] [PATCH v5 4/5] i40e: add hardware initialization Helin Zhang
2014-10-21  3:14       ` [dpdk-dev] [PATCH v5 5/5] app/testpmd: add commands to support hash filter Helin Zhang
2014-11-07  3:45       ` [dpdk-dev] [PATCH v5 0/5] Support configuring hash functions Chen, Erlu
2014-11-07  6:12       ` Chen, Erlu
2014-11-19 14:58       ` [dpdk-dev] [PATCH v6 0/3] " Helin Zhang
2014-11-19 14:58         ` [dpdk-dev] [PATCH v6 1/3] i40e: Use constant as the default hash keys Helin Zhang
2014-11-19 14:58         ` [dpdk-dev] [PATCH v6 2/3] i40e: support of controlling hash functions Helin Zhang
2014-11-19 14:58         ` [dpdk-dev] [PATCH v6 3/3] app/testpmd: add commands to support " Helin Zhang
2014-11-27 15:45         ` [dpdk-dev] [PATCH v6 0/3] Support configuring " Thomas Monjalon
2014-11-27 16:17           ` Zhang, Helin
2014-11-28 12:14         ` [dpdk-dev] [PATCH v7 0/4] " Helin Zhang
2014-11-28 12:14           ` [dpdk-dev] [PATCH v7 1/4] ethdev: code style fixes Helin Zhang
2014-11-28 12:14           ` [dpdk-dev] [PATCH v7 2/4] i40e: use constant as the default hash keys Helin Zhang
2014-11-28 12:14           ` [dpdk-dev] [PATCH v7 3/4] i40e: support of controlling hash functions Helin Zhang
2014-11-28 12:52             ` Ananyev, Konstantin
2014-11-28 12:14           ` [dpdk-dev] [PATCH v7 4/4] app/testpmd: app/testpmd: add commands to support " Helin Zhang
2014-12-02  2:19           ` [dpdk-dev] [PATCH v8 0/4] Support configuring " Helin Zhang
2014-12-02  2:19             ` [dpdk-dev] [PATCH v8 1/4] ethdev: code style fixes Helin Zhang
2014-12-02  2:19             ` [dpdk-dev] [PATCH v8 2/4] i40e: use constant as the default hash keys Helin Zhang
2014-12-02  2:19             ` [dpdk-dev] [PATCH v8 3/4] i40e: support of controlling hash functions Helin Zhang
2015-01-20  7:54               ` Thomas Monjalon
2015-01-21  0:13                 ` Zhang, Helin
2015-01-22  7:44                 ` Zhang, Helin
2014-12-02  2:19             ` [dpdk-dev] [PATCH v8 4/4] app/testpmd: add commands to support " Helin Zhang
2014-12-02 13:15             ` [dpdk-dev] [PATCH v8 0/4] Support configuring " Ananyev, Konstantin
2015-01-22  7:36             ` [dpdk-dev] [PATCH v9 0/5] " Helin Zhang
2015-01-22  7:36               ` [dpdk-dev] [PATCH v9 1/5] i40e: use constant as the default hash keys Helin Zhang
2015-01-22  7:36               ` [dpdk-dev] [PATCH v9 2/5] ethdev: code style fixes Helin Zhang
2015-01-22  7:36               ` [dpdk-dev] [PATCH v9 3/5] ethdev: support of configuring hash functions Helin Zhang
2015-01-22  7:36               ` [dpdk-dev] [PATCH v9 4/5] i40e: support of controlling " Helin Zhang
2015-01-22  7:36               ` [dpdk-dev] [PATCH v9 5/5] app/testpmd: add commands to support " Helin Zhang
     [not found]                 ` <5028514.8nkR6oWFO2@xps13>
2015-02-03  2:35                   ` Zhang, Helin
2014-09-30  6:20 ` [dpdk-dev] [PATCH v3 2/7] ethdev: add interfaces and relevant for filter control Helin Zhang
2014-09-30  6:20 ` [dpdk-dev] [PATCH v3 3/7] ethdev: add structures and enum for hash " Helin Zhang
2014-09-30  6:20 ` [dpdk-dev] [PATCH v3 4/7] i40e: add hash filter control implementation Helin Zhang
2014-09-30  6:20 ` [dpdk-dev] [PATCH v3 5/7] i40e: add hardware initialization Helin Zhang
2014-09-30  6:20 ` [dpdk-dev] [PATCH v3 6/7] i40e: Use constant random hash keys Helin Zhang
2014-09-30  6:20 ` [dpdk-dev] [PATCH v3 7/7] app/testpmd: add commands to support hash filter control Helin Zhang

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