From: Arnd Bergmann <arnd@arndb.de>
Subject: Re: [patch 4/15] fs/logfs/compr.c
Date: Thu, 10 Apr 2008 16:13:47 +0200
Message-ID: <200804101613.48465.arnd@arndb.de>
References: <20080401181308.512473173@logfs.org>
	<20080401181332.853833004@logfs.org>
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Cc: linux-fsdevel@vger.kernel.org, linux-mtd@lists.infradead.org,
	linux-kernel@vger.kernel.org
To: joern@logfs.org
In-Reply-To: <20080401181332.853833004@logfs.org>
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On Tuesday 01 April 2008, joern@logfs.org wrote:
> +
> +static DEFINE_MUTEX(compr_mutex);
> +static struct z_stream_s stream;
> +

How much time is spent in the compression code? Would it be helpful
to have a percpu stream and do preempt_disable around it instead
of the mutex?

That would improve parallelism and cache-locality of the compression,
at the cost of adding a source of latency to preemptible kernels.

	Arnd <><

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