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From: Nayna Jain <nayna@linux.vnet.ibm.com>
To: linux-integrity@vger.kernel.org
Cc: zohar@linux.vnet.ibm.com, linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org, peterhuewe@gmx.de,
	jarkko.sakkinen@linux.intel.com, tpmdd@selhorst.net,
	jgunthorpe@obsidianresearch.com, patrickc@us.ibm.com,
	Nayna Jain <nayna@linux.vnet.ibm.com>
Subject: [RFC PATCH 3/3] tpm: tpm_msleep() with finer granularity improves performance
Date: Wed, 28 Feb 2018 14:18:28 -0500	[thread overview]
Message-ID: <20180228191828.20056-3-nayna@linux.vnet.ibm.com> (raw)
In-Reply-To: <20180228191828.20056-1-nayna@linux.vnet.ibm.com>

When 'commit 9f3fc7bcddcb ("tpm: replace msleep() with  usleep_range()
in TPM 1.2/2.0 generic drivers")' was upstreamed, it replaced the
msleep() calls with usleep_range(), but did not change the
granularity of the calls. They're still defined in terms of msec.
Test results show that refining the granularity further improves
the performance. We're posting this patch as an RFC to show that there
needs to be another function which allows finer granularity.

After this change, performance on a TPM 1.2 with an 8 byte
burstcount for 1000 extends improved from ~10.7sec to ~6.9sec.

Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com>
---
 drivers/char/tpm/tpm.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 7e797377e1eb..8cad6bfc5f46 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -522,8 +522,7 @@ int tpm_pm_resume(struct device *dev);
 
 static inline void tpm_msleep(unsigned int delay_msec)
 {
-	usleep_range((delay_msec * 1000) - TPM_TIMEOUT_RANGE_US,
-		     delay_msec * 1000);
+	usleep_range((delay_msec * 1000) / 10, (delay_msec * 1000) / 2);
 };
 
 struct tpm_chip *tpm_chip_find_get(struct tpm_chip *chip);
-- 
2.13.3

WARNING: multiple messages have this Message-ID (diff)
From: nayna@linux.vnet.ibm.com (Nayna Jain)
To: linux-security-module@vger.kernel.org
Subject: [RFC PATCH 3/3] tpm: tpm_msleep() with finer granularity improves performance
Date: Wed, 28 Feb 2018 14:18:28 -0500	[thread overview]
Message-ID: <20180228191828.20056-3-nayna@linux.vnet.ibm.com> (raw)
In-Reply-To: <20180228191828.20056-1-nayna@linux.vnet.ibm.com>

When 'commit 9f3fc7bcddcb ("tpm: replace msleep() with  usleep_range()
in TPM 1.2/2.0 generic drivers")' was upstreamed, it replaced the
msleep() calls with usleep_range(), but did not change the
granularity of the calls. They're still defined in terms of msec.
Test results show that refining the granularity further improves
the performance. We're posting this patch as an RFC to show that there
needs to be another function which allows finer granularity.

After this change, performance on a TPM 1.2 with an 8 byte
burstcount for 1000 extends improved from ~10.7sec to ~6.9sec.

Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com>
---
 drivers/char/tpm/tpm.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 7e797377e1eb..8cad6bfc5f46 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -522,8 +522,7 @@ int tpm_pm_resume(struct device *dev);
 
 static inline void tpm_msleep(unsigned int delay_msec)
 {
-	usleep_range((delay_msec * 1000) - TPM_TIMEOUT_RANGE_US,
-		     delay_msec * 1000);
+	usleep_range((delay_msec * 1000) / 10, (delay_msec * 1000) / 2);
 };
 
 struct tpm_chip *tpm_chip_find_get(struct tpm_chip *chip);
-- 
2.13.3

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  parent reply	other threads:[~2018-02-28 19:19 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-28 19:18 [PATCH 1/3] tpm: move TPM_POLL_SLEEP from tpm_tis_core.c to tpm.h Nayna Jain
2018-02-28 19:18 ` Nayna Jain
2018-02-28 19:18 ` [PATCH 2/3] tpm: reduce poll sleep time between send() and recv() in tpm_transmit() Nayna Jain
2018-02-28 19:18   ` Nayna Jain
2018-03-01  9:22   ` Jarkko Sakkinen
2018-03-01  9:22     ` Jarkko Sakkinen
2018-03-01 18:56     ` Nayna Jain
2018-03-01 18:56       ` Nayna Jain
2018-03-01 18:56       ` Nayna Jain
2018-03-05 10:56       ` Jarkko Sakkinen
2018-03-05 10:56         ` Jarkko Sakkinen
2018-03-05 10:56         ` Jarkko Sakkinen
2018-03-05 18:01         ` Jarkko Sakkinen
2018-03-05 18:01           ` Jarkko Sakkinen
2018-03-05 18:01           ` Jarkko Sakkinen
2018-03-05 19:07           ` Mimi Zohar
2018-03-05 19:07             ` Mimi Zohar
2018-03-05 19:07             ` Mimi Zohar
2018-03-06 11:06             ` Jarkko Sakkinen
2018-03-06 11:06               ` Jarkko Sakkinen
2018-02-28 19:18 ` Nayna Jain [this message]
2018-02-28 19:18   ` [RFC PATCH 3/3] tpm: tpm_msleep() with finer granularity improves performance Nayna Jain
2018-03-01  9:58   ` Jarkko Sakkinen
2018-03-01  9:58     ` Jarkko Sakkinen
2018-03-02  8:13     ` Nayna Jain
2018-03-02  8:13       ` Nayna Jain
2018-03-02  8:13       ` Nayna Jain
2018-03-01  8:37 ` [PATCH 1/3] tpm: move TPM_POLL_SLEEP from tpm_tis_core.c to tpm.h Jarkko Sakkinen
2018-03-01  8:37   ` Jarkko Sakkinen
2018-03-01 18:44   ` Nayna Jain
2018-03-01 18:44     ` Nayna Jain
2018-03-01 18:44     ` Nayna Jain

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