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Date:   Mon, 5 Dec 2022 16:31:16 +0000
From:   Matthew Wilcox <willy@infradead.org>
To:     Jesper Dangaard Brouer <jbrouer@redhat.com>
Cc:     Jesper Dangaard Brouer <hawk@kernel.org>,
        Ilias Apalodimas <ilias.apalodimas@linaro.org>,
        brouer@redhat.com, netdev@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 00/24] Split page pools from struct page
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On Mon, Dec 05, 2022 at 04:34:10PM +0100, Jesper Dangaard Brouer wrote:
> I have a micro-benchmark [1][2], that I want to run on this patchset.
> Reducing the asm code 'text' size is less likely to improve a
> microbenchmark. The 100Gbit mlx5 driver uses page_pool, so perhaps I can
> run a packet benchmark that can show the (expected) performance improvement.
> 
> [1] https://github.com/netoptimizer/prototype-kernel/blob/master/kernel/lib/bench_page_pool_simple.c
> [2] https://github.com/netoptimizer/prototype-kernel/blob/master/kernel/lib/bench_page_pool_cross_cpu.c

Appreciate it!  I'm not expecting any performance change outside noise,
but things do surprise me.  I'd appreciate it if you'd test with a
"distro" config, ie enabling CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP so
we show the most expensive case.

> > I've only converted one user of the page_pool APIs to use the new netmem
> > APIs, all the others continue to use the page based ones.
> > 
> 
> I guess we/netdev-devels need to update the NIC drivers that uses page_pool.

Oh, it's not a huge amount of work, and I don't mind doing it.  I only
did one in order to show the kinds of changes that are needed.  I can
do the mlx5 conversion now ...