Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <CABWYdi0c6__rh-K7dcM_pkf9BJdTRtAU08M43KO9ME4-dsgfoQ@mail.gmail.com>
 <20230706062045.xwmwns7cm4fxd7iu@google.com> <CABWYdi2pBaCrdKcM37oBomc+5W8MdRp1HwPpOExBGYfZitxyWA@mail.gmail.com>
In-Reply-To: <CABWYdi2pBaCrdKcM37oBomc+5W8MdRp1HwPpOExBGYfZitxyWA@mail.gmail.com>
From:   Ivan Babrou <ivan@cloudflare.com>
Date:   Fri, 14 Jul 2023 17:14:19 -0700
Message-ID: <CABWYdi2L_qp8SmZ_w3pSSracYHEVku3TaBoXL7E0Nzn7CN3neg@mail.gmail.com>
Subject: Re: Expensive memory.stat + cpu.stat reads
To:     Shakeel Butt <shakeelb@google.com>
Cc:     cgroups@vger.kernel.org, Linux MM <linux-mm@kvack.org>,
        kernel-team <kernel-team@cloudflare.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Muchun Song <muchun.song@linux.dev>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Mon, Jul 10, 2023 at 4:21=E2=80=AFPM Ivan Babrou <ivan@cloudflare.com> w=
rote:
> The fast one is v6.1.37 and the slow one is v6.1.25. I'm not sure if
> the kernel version makes a difference or if it's a matter of uptime /
> traffic profile. The data is from two different locations. The fast
> location has gone through an expansion, which meant a full reboot with
> a kernel upgrade, so maybe that affected things:
>
> * https://i.imgur.com/x8uyMaF.png
>
> Let me try to reboot the slow location and see if there's any lasting
> improvement.

There is no correlation with the kernel version, v6.1.38 is slow too:

completed: 23.09s [manual / cpu-stat + mem-stat]
completed:  0.30s [manual / mem-stat]
completed:  0.64s [manual / cpu-stat]