From: Mimi Zohar <zohar@linux.vnet.ibm.com>
To: Alexander Steffen <Alexander.Steffen@infineon.com>,
jarkko.sakkinen@linux.intel.com, nayna@linux.vnet.ibm.com,
kgold@linux.vnet.ibm.com, linux-integrity@vger.kernel.org
Subject: Re: [RFC][PATCH 8/9] tpm_tis_spi: add delay between wait state retries
Date: Mon, 15 Jan 2018 17:30:50 -0500 [thread overview]
Message-ID: <1516055450.6607.91.camel@linux.vnet.ibm.com> (raw)
In-Reply-To: <db63c75f-464d-2fbc-3e97-ea3ef162cea5@infineon.com>
> What would be a better implementation? No delay and simply retry for
> five seconds?
>
> What TPMs are you using for your tests? At least for the TPMs that I
> have available for my tests (with a FIFO size of ~256 bytes) I would not
> expect any wait states for extend commands.
The TPM burstcount is 32. Unfortunately, with this patch set the
performance on the pi is worse than without it. Without this patch
set we're seeing ~14 secs for a thousand measurements vs. either ~38s
or ~23s, depending on the wait sleep length introduced in patch 8/9.
This testing was done on a pi with an emulated SPI bus.
On systems with a large burstcount, there is no difference, but on
systems with a small burstcount, we're seeing an improvement of ~39%
(~14s base time, ~8.5 with patches).
Does anyone have a system with a TPM on a real SPI bus and is willing
to test this patch set?
thanks,
Mimi
next prev parent reply other threads:[~2018-01-15 22:30 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-08 18:46 [RFC][PATCH 0/9] tpm: fix driver so that burstcount can be safely ignored Alexander Steffen
2017-12-08 18:46 ` [RFC][PATCH 1/9] tpm_tis_core: clean up whitespace Alexander Steffen
2018-01-18 17:11 ` Jarkko Sakkinen
2017-12-08 18:46 ` [RFC][PATCH 2/9] tpm_tis_core: access single TIS registers before doing complex transfers Alexander Steffen
2018-01-18 17:16 ` Jarkko Sakkinen
2017-12-08 18:46 ` [RFC][PATCH 3/9] tpm_tis_core: correctly wait for flags to become zero Alexander Steffen
2018-01-18 17:49 ` Jarkko Sakkinen
2018-01-18 17:58 ` Jarkko Sakkinen
2018-01-18 17:59 ` Jarkko Sakkinen
2017-12-08 18:46 ` [RFC][PATCH 4/9] tpm_tis_core: send all data in single operation Alexander Steffen
2017-12-19 9:01 ` Nayna Jain
2018-01-18 18:04 ` Jarkko Sakkinen
2017-12-08 18:46 ` [RFC][PATCH 5/9] tpm_tis_core: use XDATA_FIFO for transfers if available Alexander Steffen
2018-01-18 18:20 ` Jarkko Sakkinen
2017-12-08 18:46 ` [RFC][PATCH 6/9] tpm_tis_spi: fix sending wrong data during wait state handling Alexander Steffen
2018-01-18 18:26 ` Jarkko Sakkinen
2017-12-08 18:46 ` [RFC][PATCH 7/9] tpm_tis_spi: release CS line when wait state handling fails Alexander Steffen
2018-01-18 18:30 ` Jarkko Sakkinen
2017-12-08 18:46 ` [RFC][PATCH 8/9] tpm_tis_spi: add delay between wait state retries Alexander Steffen
2018-01-11 19:46 ` Mimi Zohar
2018-01-12 8:28 ` Alexander Steffen
2018-01-12 14:53 ` Mimi Zohar
2018-01-15 22:30 ` Mimi Zohar [this message]
2018-01-17 17:15 ` Mimi Zohar
2018-01-17 18:58 ` Alexander Steffen
2018-01-18 18:32 ` Jarkko Sakkinen
2017-12-08 18:46 ` [RFC][PATCH 9/9] tpm: ignore burstcount to improve tpm_tis send() performance Alexander Steffen
2017-12-15 12:04 ` [RFC][PATCH 0/9] tpm: fix driver so that burstcount can be safely ignored Jarkko Sakkinen
2017-12-24 20:41 ` Jarkko Sakkinen
2018-01-04 13:11 ` Alexander.Steffen
2018-01-05 6:46 ` Nayna Jain
2018-01-05 7:38 ` Alexander Steffen
2018-01-08 10:50 ` Jarkko Sakkinen
2018-01-08 10:49 ` Jarkko Sakkinen
2017-12-19 8:53 ` Nayna Jain
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