From: Christoph Hellwig <hch@infradead.org>
To: "Luca Porzio (lporzio)" <lporzio@micron.com>
Cc: "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Alex Lemberg <Alex.Lemberg@sandisk.com>,
"ulf.hansson@linaro.org" <ulf.hansson@linaro.org>,
"tlinder@codeaurora.org" <tlinder@codeaurora.org>
Subject: Re: REQ_META performance impact on eMMC
Date: Sun, 21 Jun 2015 07:02:33 -0700 [thread overview]
Message-ID: <20150621140233.GA28075@infradead.org> (raw)
In-Reply-To: <26E7A31274623843B0E8CF86148BFE32011C36E354@NTXBOIMBX08.micron.com>
On Fri, Jun 19, 2015 at 04:06:49PM +0000, Luca Porzio (lporzio) wrote:
> This performance impact comes from the existing MMC SW driver solution where each IO request marked with REQ_META is handled as a "Reliable Write" operation.
> Pretty much as a as a FUA write access, a "Reliable write" means that the data will be written to the non-volatile memory.
> Due to the fact that every REQ_META is immediately bypassing the internal cache of eMMC device, write performance is affected significantly.
>
> Please advise how critical is to send REQ_META as "Reliable Write"?
Not at all.
> Can REQ_META be sent as a regular Write operation?
Yes, and it should.
The MMC driver is doing something completely dumb here.
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prev parent reply other threads:[~2015-06-21 14:02 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-19 16:06 REQ_META performance impact on eMMC Luca Porzio (lporzio)
2015-06-21 14:02 ` Christoph Hellwig [this message]
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