From: Jarkko Nikula <jarkko.nikula@linux.intel.com>
To: Lucas De Marchi <lucas.demarchi@intel.com>, linux-i2c@vger.kernel.org
Cc: christian.ruppert@alitech.com, linux-kernel@vger.kernel.org,
mika.westerberg@linux.intel.com,
"José Roberto de Souza" <jose.souza@intel.com>,
"Wolfram Sang" <wsa@the-dreams.de>
Subject: Re: [PATCH v3 1/3] i2c: designware: wait for disable/enable only if necessary
Date: Tue, 16 Aug 2016 16:59:55 +0300 [thread overview]
Message-ID: <bb134298-26de-c565-bf7a-78302914991f@linux.intel.com> (raw)
In-Reply-To: <1469743424-2480-2-git-send-email-lucas.demarchi@intel.com>
Hi, + Wolfram
On 07/29/2016 01:03 AM, Lucas De Marchi wrote:
> From: José Roberto de Souza <jose.souza@intel.com>
>
> If we aren't going to continue using the controller we can just disable
> it instead of waiting for it to complete. The biggest improvement here
> is when a I2C transaction is completed and it doesn't block until
> the adapter is disabled. When a new transfer is needed we will disable
> and wait for its completion.
>
> This way the adapter will continue changing its state in parallel to the
> execution of the thread that requested the I2C transaction saving most
> of the time 25~250 usec per I2C transaction.
>
> A simple program doing a register read (1 byte write, 1 byte read)
> alternating on 2 different slaves repeated 25k times for each and
> measurements taken 4 times we get:
>
> perf stat -r4 chrt -f 10 ./i2c-test /dev/i2c-1 25000 0x40 0x6 0x1e 0x00
>
> Before:
> 30.879317977 seconds time elapsed ( +- 14.83% )
> After:
> 8.638705161 seconds time elapsed ( +- 5.90% )
>
> Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> ---
> drivers/i2c/busses/i2c-designware-core.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
next prev parent reply other threads:[~2016-08-16 14:00 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-28 22:03 [PATCH v3 0/3] i2c: designware: improve performance for transfers Lucas De Marchi
2016-07-28 22:03 ` [PATCH v3 1/3] i2c: designware: wait for disable/enable only if necessary Lucas De Marchi
2016-08-16 13:59 ` Jarkko Nikula [this message]
2016-07-28 22:03 ` [PATCH v3 2/3] i2c: designware: detect when dynamic tar update is possible Lucas De Marchi
2016-08-16 14:00 ` Jarkko Nikula
2016-08-16 14:07 ` De Marchi, Lucas
2016-08-17 8:05 ` Jarkko Nikula
2016-08-17 12:48 ` De Marchi, Lucas
2016-07-28 22:03 ` [PATCH v3 3/3] i2c: designware: do not disable adapter after transfer Lucas De Marchi
2016-08-16 14:00 ` Jarkko Nikula
2016-08-12 14:59 ` [PATCH v3 0/3] i2c: designware: improve performance for transfers Christian Ruppert
2016-08-15 12:34 ` De Marchi, Lucas
2016-08-16 12:14 ` Wolfram Sang
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