From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pavel Machek <pavel@ucw.cz>
Subject: Re: [PATCH v2 1/1] drivers core: multi-threading device shutdown
Date: Wed, 23 May 2018 12:40:29 +0200
Message-ID: <20180523104029.GC15312@amd>
References: <20180505154040.28614-1-pasha.tatashin@oracle.com>
 <20180505154040.28614-2-pasha.tatashin@oracle.com>
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Cc: steven.sistare@oracle.com, daniel.m.jordan@oracle.com,
        linux-kernel@vger.kernel.org, jeffrey.t.kirsher@intel.com,
        intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
        gregkh@linuxfoundation.org, alexander.duyck@gmail.com,
        tobin@apporbit.com
To: Pavel Tatashin <pasha.tatashin@oracle.com>
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Hi!

> When system is rebooted, halted or kexeced device_shutdown() is
> called.
>=20
> This function shuts down every single device by calling either:
>=20
> 	dev->bus->shutdown(dev)
> 	dev->driver->shutdown(dev)
=2E..
> Finally, with ixgbe_shutdown() it takes 0.37 for each device, but that ti=
me
> is spread all over the place, with bigger offenders:
>=20
>     ixgbe_shutdown
>       __ixgbe_shutdown
>         ixgbe_close_suspend
>           ixgbe_down
>             ixgbe_init_hw_generic
>               ixgbe_reset_hw_X540
>                 msleep(100);                        0.104483472
>                 ixgbe_get_san_mac_addr_generic      0.048414851
>                 ixgbe_get_wwn_prefix_generic        0.048409893
>               ixgbe_start_hw_X540
>                 ixgbe_start_hw_generic
>                   ixgbe_clear_hw_cntrs_generic      0.048581502
>                   ixgbe_setup_fc_generic            0.024225800

ixgbe is network card, right? So ... it does not have any persistent
state and no moving parts, and there's no reason we could not "just
power it down"?
>  /*

--=20
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