From: Tejun Heo <tj@kernel.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "Jesper Dangaard Brouer" <brouer@redhat.com>,
"Björn Töpel" <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
Date: Fri, 20 Dec 2019 08:34:41 -0800 [thread overview]
Message-ID: <20191220163441.GH2914998@devbig004.ftw2.facebook.com> (raw)
In-Reply-To: <a66e79b1-41a8-08f6-8dc2-37ce7a5fff53@gmail.com>
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
prev parent reply other threads:[~2019-12-20 16:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAJ+HfNgNAzvdBw7gBJTCDQsne-HnWm90H50zNvXBSp4izbwFTA@mail.gmail.com>
2019-12-20 9:34 ` Percpu variables, benchmarking, and performance weirdness Jesper Dangaard Brouer
2019-12-20 15:12 ` Tejun Heo
2019-12-20 15:36 ` Christopher Lameter
2019-12-20 17:10 ` Dennis Zhou
2019-12-20 16:22 ` Eric Dumazet
2019-12-20 16:34 ` Tejun Heo [this message]
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