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: <20220720204414.1.I699244ea7efbd326a34a6dfd9b5a31e78400cf68@changeid>
In-Reply-To: <20220720204414.1.I699244ea7efbd326a34a6dfd9b5a31e78400cf68@changeid>
From:   Stanley Chu <chu.stanley@gmail.com>
Date:   Mon, 1 Aug 2022 11:23:42 +0800
Message-ID: <CAGaU9a_Tm_awy+EAaYpv1Aj+URKkrD1yZDY2dWbhoWj0qUr5uw@mail.gmail.com>
Subject: Re: [PATCH] ufs: core: ufshcd: use CLOCK_BOOTTIME for debugging timestamps
To:     Daniil Lunev <dlunev@chromium.org>
Cc:     Adrian Hunter <adrian.hunter@intel.com>,
        Bart Van Assche <bvanassche@acm.org>,
        Alim Akhtar <alim.akhtar@samsung.com>,
        Avri Altman <avri.altman@wdc.com>,
        Bean Huo <beanhuo@micron.com>,
        Daejun Park <daejun7.park@samsung.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hi Daniil,

On Wed, Jul 20, 2022 at 6:49 PM Daniil Lunev <dlunev@chromium.org> wrote:
>
> CLOCK_MONOTONIC is not advanced when the system is in suspend. This
> becomes problematic when debugging issues related to suspend-resume:
> the timestamps printed by ufshcd_print_trs can not be correlated with
> dmesg entries, which are timestamped with CLOCK_BOOTTIME.
>
> This CL changes the used clock to CLOCK_BOOTTIME for the informational
> timestamp variables and adds mirroring CLOCK_BOOTIME instances for
> variables used in subsequent derevations (to not change the semantics of
> those derevations).
>
> Signed-off-by: Daniil Lunev <dlunev@chromium.org>
>

Regarding the suspend/resume issue breakdown with aligned timestamp
with the dmesg logs, perhaps we need to use "sched_clock()" since it
is the timestamp used by dmesg?

Thanks,
Stanley