From: "Van Haaren, Harry" <harry.van.haaren@intel.com>
To: "Horton, Remy" <remy.horton@intel.com>,
Andriy Berestovskyy <aber@semihalf.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH] keepalive: fix keepalive state alignment
Date: Tue, 23 Jan 2018 10:27:40 +0000 [thread overview]
Message-ID: <E923DB57A917B54B9182A2E928D00FA650FF40D9@IRSMSX102.ger.corp.intel.com> (raw)
In-Reply-To: <14e524b4-b844-63ef-b686-6bddf468a464@intel.com>
> From: Horton, Remy
> Sent: Tuesday, January 23, 2018 10:17 AM
> To: Andriy Berestovskyy <aber@semihalf.com>; Van Haaren, Harry
> <harry.van.haaren@intel.com>
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH] keepalive: fix keepalive state alignment
>
>
> On 22/01/2018 18:20, Andriy Berestovskyy wrote:
> [..]
> > On Fri, Jan 19, 2018 at 6:31 PM, Van Haaren, Harry
> > <harry.van.haaren@intel.com> wrote:
> >> These changes do reduce false-sharing however is there actually a
> >> performance benefit? A lot of cache space will be taken up if each
> >> core requires its own cache line, which will reduce performance
> >> again.. it's a tradeoff.
> [..]
> > 2. The original code (prior e70a61ad50ab "keepalive: export states")
> > had each element aligned to the cache line, not the whole array.
>
> Aligning each flag element was the original intention, so I see no issue
> in restoring it. The monitoring core only reads the entries within
> state_flags for which the corresponding active_core is set, so
> ultimately the trade-off in cache line usage is one made by the
> application when it decides which cores need monitoring.
>
> ..Remy
No objection here - just making sure the change was intentional
and the effects are considered.
@Remy as you're the Keepalive maintainer I'll leave Acking to you :)
-Harry
prev parent reply other threads:[~2018-01-23 10:27 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-19 14:47 Andriy Berestovskyy
2018-01-19 17:31 ` Van Haaren, Harry
2018-01-22 18:20 ` Andriy Berestovskyy
2018-01-23 10:16 ` Remy Horton
2018-01-23 10:27 ` Van Haaren, Harry [this message]
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