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From: "Burakov, Anatoly" <anatoly.burakov@intel.com>
To: Olivier Matz <olivier.matz@6wind.com>,
	dev@dpdk.org, "Ananyev,
	Konstantin" <konstantin.ananyev@intel.com>,
	"Richardson, Bruce" <bruce.richardson@intel.com>
Subject: Re: [dpdk-dev] [PATCH] ring: relax alignment constraint on ring structure
Date: Fri, 25 May 2018 11:59:29 +0100	[thread overview]
Message-ID: <460fd61f-4346-752b-02c9-5ac952ea5215@intel.com> (raw)
In-Reply-To: <20180403132644.23729-1-olivier.matz@6wind.com>

On 03-Apr-18 2:26 PM, Olivier Matz wrote:
> The initial objective of
> commit d9f0d3a1ffd4 ("ring: remove split cacheline build setting")
> was to add an empty cache line betwee, the producer and consumer
> data (on platform with cache line size = 64B), preventing from
> having them on adjacent cache lines.
> 
> Following discussion on the mailing list, it appears that this
> also imposes an alignment constraint that is not required.
> 
> This patch removes the extra alignment constraint and adds the
> empty cache lines using padding fields in the structure. The
> size of rte_ring structure and the offset of the fields remain
> the same on platforms with cache line size = 64B:
> 
>    rte_ring = 384
>    rte_ring.name = 0
>    rte_ring.flags = 32
>    rte_ring.memzone = 40
>    rte_ring.size = 48
>    rte_ring.mask = 52
>    rte_ring.prod = 128
>    rte_ring.cons = 256
> 
> But it has an impact on platform where cache line size is 128B:
> 
>    rte_ring = 384        -> 768
>    rte_ring.name = 0
>    rte_ring.flags = 32
>    rte_ring.memzone = 40
>    rte_ring.size = 48
>    rte_ring.mask = 52
>    rte_ring.prod = 128   -> 256
>    rte_ring.cons = 256   -> 512
> 
> Link: http://dpdk.org/dev/patchwork/patch/25039/
> Suggested-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
> ---

This patch causes eal_flags_autotest to hang on FreeBSD. Root cause at 
this time is unknown, but this is a weird one - the test seems to hang 
while doing read() in bsd/eal_thread.c:59. Reverting this patch on top 
of rc5 results in eal_flags_autotest passing.

-- 
Thanks,
Anatoly

  parent reply	other threads:[~2018-05-25 10:59 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-30 14:26 [dpdk-dev] [RFC] " Olivier Matz
2017-07-20  8:52 ` Olivier Matz
2018-04-03 13:26 ` [dpdk-dev] [PATCH] " Olivier Matz
2018-04-03 15:07   ` Jerin Jacob
2018-04-03 15:25     ` Olivier Matz
2018-04-03 15:37       ` Jerin Jacob
2018-04-03 15:56         ` Olivier Matz
2018-04-03 16:42           ` Jerin Jacob
2018-04-04 23:38             ` Ananyev, Konstantin
2018-04-05  8:01               ` Jerin Jacob
2018-04-05 13:49                 ` Ananyev, Konstantin
2018-04-06  1:26                   ` Jerin Jacob
2018-04-11  0:33                     ` Ananyev, Konstantin
2018-04-11  2:48                       ` Jerin Jacob
2018-04-11  8:40                         ` Ananyev, Konstantin
2018-04-17 22:15                     ` Thomas Monjalon
2018-05-25 10:59   ` Burakov, Anatoly [this message]
2018-05-25 12:18     ` Burakov, Anatoly
2018-05-25 14:57       ` Burakov, Anatoly
2018-05-25 15:17         ` Olivier Matz

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