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Date:   Fri, 20 Dec 2019 08:34:41 -0800
From:   Tejun Heo <tj@kernel.org>
To:     Eric Dumazet <eric.dumazet@gmail.com>
Cc:     Jesper Dangaard Brouer <brouer@redhat.com>,
        =?iso-8859-1?Q?Bj=F6rn_T=F6pel?= <bjorn.topel@gmail.com>,
        bpf <bpf@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        Christoph Lameter <cl@linux.com>,
        Dennis Zhou <dennis@kernel.org>
Subject: Re: Percpu variables, benchmarking, and performance weirdness
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On Fri, Dec 20, 2019 at 08:22:02AM -0800, Eric Dumazet wrote:
> I definitely seen expensive per-cpu updates in the stack.
> (SNMP counters, or per-cpu stats for packets/bytes counters)
> 
> It might be nice to have an option to use 2M pages.
> 
> (I recall sending some patches in the past about using high-order pages for vmalloc,
> but this went nowhere)

Yeah, the percpu allocator implementation is half-way prepared for
that.  There just hasn't been a real need for that yet.  If this
actually is a difference coming from tlb pressure, this might be it, I
guess?

Thanks.

-- 
tejun