netdev - Re: [PATCH RFC 01/26] netfilter: Replace spin_unlock

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Message-ID: <ee509620-8ba5-be45-743e-f077a457c01d@colorfullife.com>
Date:   Thu, 6 Jul 2017 20:43:28 +0200
From:   Manfred Spraul <manfred@...orfullife.com>
To:     Alan Stern <stern@...land.harvard.edu>
Cc:     paulmck@...ux.vnet.ibm.com, linux-kernel@...r.kernel.org,
        netfilter-devel@...r.kernel.org, netdev@...r.kernel.org,
        oleg@...hat.com, akpm@...ux-foundation.org, mingo@...hat.com,
        dave@...olabs.net, tj@...nel.org, arnd@...db.de,
        linux-arch@...r.kernel.org, will.deacon@....com,
        peterz@...radead.org, parri.andrea@...il.com,
        torvalds@...ux-foundation.org,
        Pablo Neira Ayuso <pablo@...filter.org>,
        Jozsef Kadlecsik <kadlec@...ckhole.kfki.hu>,
        Florian Westphal <fw@...len.de>,
        "David S. Miller" <davem@...emloft.net>, coreteam@...filter.org,
        1vier1@....de
Subject: Re: [PATCH RFC 01/26] netfilter: Replace spin_unlock_wait() with
 lock/unlock pair

Hi Alan,

On 07/03/2017 09:57 PM, Alan Stern wrote:
>
> (Alternatively, you could make nf_conntrack_all_unlock() do a
> lock+unlock on all the locks in the array, just like
> nf_conntrack_all_lock().  But of course, that would be a lot less
> efficient.)
Hmmmm.

Someone with a weakly ordered system who can test this?
semop() has a very short hotpath.

Either with aim9.shared_memory.ops_per_sec or

#sem-scalebench -t 10 -m 0
https://github.com/manfred-colorfu/ipcscale/blob/master/sem-scalebench.cpp
--
     Manfred

View attachment "0002-ipc-sem.c-avoid-smp_load_acuqire-in-the-hot-path.patch" of type "text/x-patch" (3331 bytes)