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Date:   Thu, 26 Mar 2020 17:47:32 +0100
From:   Petr Malat <oss@malat.biz>
To:     Nick Terrell <nickrterrell@gmail.com>
Cc:     Nick Terrell <terrelln@fb.com>, linux-kernel@vger.kernel.org,
        Chris Mason <clm@fb.com>, linux-kbuild@vger.kernel.org,
        x86@kernel.org, gregkh@linuxfoundation.org,
        Kees Cook <keescook@chromium.org>,
        Kernel Team <Kernel-team@fb.com>,
        Adam Borowski <kilobyte@angband.pl>,
        Patrick Williams <patrickw3@fb.com>, rmikey@fb.com,
        mingo@kernel.org, Patrick Williams <patrick@stwcx.xyz>
Subject: Re: [PATCH v3 3/8] lib: add zstd support to decompress
Message-ID: <20200326164732.GA17157@ntb.petris.klfree.czf>
References: <20200325195849.407900-1-nickrterrell@gmail.com>
 <20200325195849.407900-4-nickrterrell@gmail.com>
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Hi!
On Wed, Mar 25, 2020 at 12:58:44PM -0700, Nick Terrell wrote:
> From: Nick Terrell <terrelln@fb.com>
> * Add unzstd() and the zstd decompress interface.
Here I do not understand why you limit the window size to 8MB even when
you read a larger value from the header. I do not see a reason why there
should be such a limitation at the first place and if there should be,
why it differs from ZSTD_WINDOWLOG_MAX.

I removed that limitation to be able to test it in my environment and I
found the performance is worst than with my patch by roughly 20% (on
i7-3520M), which is a major drawback considering the main motivation
to use zstd is the decompression speed. I will test on arm as well and
share the result tomorrow.
  Petr