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Date:   Thu, 8 Nov 2018 13:05:09 +0100
From:   Jean Delvare <jdelvare@suse.de>
To:     Dave Airlie <airlied@redhat.com>
Cc:     Christian =?UTF-8?B?S8O2bmln?= <christian.koenig@amd.com>,
        Takashi Iwai <tiwai@suse.de>, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
Subject: Re: Performance regression in ast drm driver
Message-ID: <20181108130509.3b2d42ff@endymion>
In-Reply-To: <20181101162707.598c1718@endymion>
References: <20181101162707.598c1718@endymion>
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On Thu, 1 Nov 2018 16:27:07 +0100, Jean Delvare wrote:
> Hi David,
> 
> The following commit:
> 
> commit 7cf321d118a825c1541b43ca45294126fd474efa
> Author: Dave Airlie
> Date:   Mon Oct 24 15:37:48 2016 +1000
> 
>     drm/drivers: add support for using the arch wc mapping API.
> 
> is causing a huge performance regression for the ast drm driver. In a
> text console, if I call "cat" on a large text file, it takes almost
> twice as much time to be displayed and scrolled completely.
> 
> Can you please check that the ast driver portion of that commit is both
> correct and complete?

And in the meantime, what bad will happen if we just revert the ast
portion of that commit?

Thanks,
-- 
Jean Delvare
SUSE L3 Support