From: Ken Goldman <kgold@linux.vnet.ibm.com>
To: unlisted-recipients:; (no To-header on input)
Cc: linux-ima-devel@lists.sourceforge.net,
linux-security-module@vger.kernel.org,
tpmdd-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org
Subject: Re: Aw: Re: [tpmdd-devel] [PATCH] tpm: improve tpm_tis send() performance by ignoring burstcount
Date: Wed, 16 Aug 2017 15:51:43 -0400 [thread overview]
Message-ID: <4eac8afa-89ff-fa02-05ba-a5c1018351af@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170814101046.5hqrkaqmfvl7ugwj@linux.intel.com>
On 8/14/2017 6:10 AM, Jarkko Sakkinen wrote:
>> Nuvoton, ST Micro, and Infineon confirmed that the TPM empties a byte from
>> the FIFO in under 1 usec. So, even with a static burst count, the entire
>> FIFO would empty in under 10 usec.
>
> Does this break anything lets say in a decade time frame? If it does, I
> will not even consider this. Can you give a definitive answer for that?
My attempt at predicting the future ...
1 - Clock speed should get faster, not slower, so the 1 usec wait state
should get shorter.
2 - TPM buffers should get larger. I'm already reading of 256 byte
buffers. So there should be fewer wait states.
3 - There is a trend toward using the CRB, making the FIFO less applicable.
4 - There is a trend away from LPC connected serial port devices,
printers, and PS/2 mouse and keyboard, and toward USB connected devices.
I assume this will continue, making the already insignificant wait
states irrelevant.
next prev parent reply other threads:[~2017-08-16 19:51 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-07 11:46 [PATCH] tpm: improve tpm_tis send() performance by ignoring burstcount Nayna Jain
2017-08-07 11:52 ` Peter Huewe
2017-08-07 14:25 ` Nayna
2017-08-08 21:50 ` Jarkko Sakkinen
2017-08-08 19:11 ` Jarkko Sakkinen
2017-08-09 20:23 ` [tpmdd-devel] " Ken Goldman
2017-08-09 20:43 ` Aw: " Peter Huewe
2017-08-11 21:54 ` Ken Goldman
[not found] ` <20170814101046.5hqrkaqmfvl7ugwj@linux.intel.com>
2017-08-16 19:51 ` Ken Goldman [this message]
2017-08-09 20:25 ` Ken Goldman
2017-08-09 21:00 ` Aw: " Peter Huewe
2017-08-11 11:14 ` Jarkko Sakkinen
2017-08-11 15:30 ` Mimi Zohar
2017-08-14 10:51 ` Jarkko Sakkinen
2017-08-14 10:56 ` Jarkko Sakkinen
2017-08-14 12:03 ` Mimi Zohar
2017-08-15 6:08 ` Jarkko Sakkinen
2017-08-14 12:12 ` Mimi Zohar
2017-08-15 6:09 ` Jarkko Sakkinen
2017-08-11 21:32 ` Aw: " Ken Goldman
2017-08-13 23:53 ` msuchanek
2017-08-15 22:02 ` Ken Goldman
2017-08-16 10:24 ` Michal Suchánek
2017-08-11 21:42 ` [Linux-ima-devel] " Ken Goldman
2017-08-08 19:07 ` Jarkko Sakkinen
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