From: Ken Goldman <kgold@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org,
tpmdd-devel@lists.sourceforge.net,
linux-ima-devel@lists.sourceforge.net
Subject: Re: [tpmdd-devel] [PATCH] tpm: improve tpm_tis send() performance by ignoring burstcount
Date: Wed, 9 Aug 2017 16:23:12 -0400 [thread overview]
Message-ID: <819e3d38-3f16-a32b-1928-c425b763d5f8@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170808191145.kggmoczd5laiccrn@linux.intel.com>
On 8/8/2017 3:11 PM, Jarkko Sakkinen wrote:
> On Mon, Aug 07, 2017 at 01:52:34PM +0200, Peter Huewe wrote:
>> Imho: NACK from my side.
> After these viewpoints definitive NACK from my side too...
I responded to the thread comments separately. However, assuming NACK
is the final response, I have a question.
The problem is the 5 msec sleep between polls of burst count. In the
case of one TPM with an 8 byte FIFO, a 32 byte transfer incurs 4 of
these sleeps.
Would another solution be to reduce the burst count poll and sleep to,
e.g., 100 usec or even 10 usec? This would probably help greatly, but
still not incur the wait states that triggered the NACK.
My worry is that the scheduler would not be able to context switch that
fast, and so we wouldn't actually see usec speed polling.
Can a kernel expert offer an opinion?
next prev parent reply other threads:[~2017-08-09 20:23 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 ` Ken Goldman [this message]
2017-08-09 20:43 ` Aw: Re: [tpmdd-devel] " Peter Huewe
2017-08-11 21:54 ` Ken Goldman
[not found] ` <20170814101046.5hqrkaqmfvl7ugwj@linux.intel.com>
2017-08-16 19:51 ` Ken Goldman
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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