From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Nayna Jain <nayna@linux.vnet.ibm.com>
Cc: linux-integrity@vger.kernel.org, zohar@linux.vnet.ibm.com,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org, peterhuewe@gmx.de,
tpmdd@selhorst.net, jgunthorpe@obsidianresearch.com,
patrickc@us.ibm.com
Subject: Re: [PATCH v4 1/2] tpm: reduce poll sleep time in tpm_transmit()
Date: Wed, 16 May 2018 17:10:35 +0300 [thread overview]
Message-ID: <20180516141035.GA10304@linux.intel.com> (raw)
In-Reply-To: <20180516055125.5685-2-nayna@linux.vnet.ibm.com>
On Wed, May 16, 2018 at 01:51:24AM -0400, Nayna Jain wrote:
> tpm_try_transmit currently checks TPM status every 5 msecs between
> send and recv. It does so in a loop for the maximum timeout as defined
> in the TPM Interface Specification. However, the TPM may return before
> 5 msecs. Thus the polling interval for each iteration can be reduced,
> which improves overall performance. This patch changes the polling sleep
> time from 5 msecs to 1 msec.
>
> Additionally, this patch renames TPM_POLL_SLEEP to TPM_TIMEOUT_POLL and
> moves it to tpm.h as an enum value.
>
> After this change, performance on a system[1] with a TPM 1.2 with an 8 byte
> burstcount for 1000 extends improved from ~14 sec to ~10.7 sec.
>
> [1] All tests are performed on an x86 based, locked down, single purpose
> closed system. It has Infineon TPM 1.2 using LPC Bus.
Already applied previous version of this.
/Jarkko
next prev parent reply other threads:[~2018-05-16 14:10 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-16 5:51 [PATCH v4 0/2] tpm: improving granularity in poll sleep times Nayna Jain
2018-05-16 5:51 ` [PATCH v4 1/2] tpm: reduce poll sleep time in tpm_transmit() Nayna Jain
2018-05-16 14:10 ` Jarkko Sakkinen [this message]
2018-05-16 5:51 ` [PATCH v4 2/2] tpm: reduce polling time to usecs for even finer granularity Nayna Jain
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