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 v3 4/5] tpm: reduce tpm_msleep() time in get_burstcount()
Date: Thu, 12 Oct 2017 14:18:35 +0300 [thread overview]
Message-ID: <20171012111835.g7uulven4whnpf5d@linux.intel.com> (raw)
In-Reply-To: <20171004102924.12355-5-nayna@linux.vnet.ibm.com>
On Wed, Oct 04, 2017 at 06:29:23AM -0400, Nayna Jain wrote:
> Currently, get_burstcount() function sleeps for 5msec in a loop
> before retrying for next query to burstcount. However, if it takes
> lesser time for TPM to return, this 5msec delay is longer
> than necessary.
>
> This patch replaces the tpm_msleep time from 5msec to 1msec.
>
> After this change, performance on a TPM 1.2 with an 8 byte
> burstcount for 1000 extends improved from ~10sec to ~9sec.
>
> Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com>
> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
> ---
> drivers/char/tpm/tpm_tis_core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index 224842e06105..826a0b9c9201 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -226,7 +226,7 @@ static int get_burstcount(struct tpm_chip *chip)
> burstcnt = (value >> 8) & 0xFFFF;
> if (burstcnt)
> return burstcnt;
> - tpm_msleep(TPM_TIMEOUT);
> + tpm_msleep(TPM_POLL_SLEEP);
> } while (time_before(jiffies, stop));
> return -EBUSY;
> }
> --
> 2.13.3
>
Would it make sense to squash this to 3/5 and merge the commit
messages?
/Jarkko
next prev parent reply other threads:[~2017-10-12 11:18 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-04 10:29 [PATCH v3 0/4] additional TPM performance improvements Nayna Jain
2017-10-04 10:29 ` [PATCH v3 1/5] tpm: move wait_for_tpm_stat() to respective driver files Nayna Jain
2017-10-10 14:57 ` Jarkko Sakkinen
2017-10-04 10:29 ` [PATCH v3 2/5] tpm: ignore burstcount to improve tpm_tis send() performance Nayna Jain
2017-10-10 15:04 ` Jarkko Sakkinen
2017-10-11 11:29 ` Nayna Jain
2017-10-04 10:29 ` [PATCH v3 3/5] tpm: reduce polling delay in tpm_tis wait_for_tpm_stat() Nayna Jain
2017-10-12 11:17 ` Jarkko Sakkinen
2017-10-04 10:29 ` [PATCH v3 4/5] tpm: reduce tpm_msleep() time in get_burstcount() Nayna Jain
2017-10-12 11:18 ` Jarkko Sakkinen [this message]
2017-10-12 13:14 ` Nayna Jain
2017-10-04 10:29 ` [PATCH v3 5/5] tpm: use tpm_msleep() value as max delay Nayna Jain
2017-10-12 11:19 ` Jarkko Sakkinen
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