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Subject[PATCH v3 0/4] additional TPM performance improvements
Date
After further discussions with the TCG Device Driver working group (ddwg),
the following changes were made:

* Check for burstcount at least once to confirm the TPM is ready to accept
the data. Similarly, query for the TPM Expect status as sanity check at
the end.

* Make the sleep for status check in the loop less than 5msec.

* Make the sleep in the loop while querying for burstcount less than
5msec.

Below is the list of patches along with the performance improvements
seen with a TPM 1.2 with an 8 byte burstcount for 1000 extends:

Patch |Improvement(time in sec)

tpm: ignore burstcount to improve tpm_tis | ~41 - ~14
send() performance.

tpm: reduce polling delay in tpm_tis | ~14 - ~10
wait_for_tpm_stat()

tpm: reduce tpm_msleep() time in | ~10 - ~9
get_burstcount()

tpm: modify tpm_msleep() function to have | ~9 - ~8
max range

Changelog v3:

* Include Jarkko's feedback to move wait_for_tpm_stat() from
tpm-interface.c to respective driver files tpm_tis_core.c and
xen-tpmfront.c.
* Remove use of module parameter ignore_burst_count and is
now alwaysed ignored in tpm tis send() operation.
* Reduce sleep() time during polling in wait_for_tpm_stat() from
5msec to 1msec for both recv() and send() operation. Version
2 of the patches had it only for send() operation.

Changelog v2:

* Add module parameter to handle ignoring of burst count during
tpm tis send() operation.
* Add improvements over sleep time to reduce delays.

Nayna Jain (5):
tpm: move wait_for_tpm_stat() to respective driver files
tpm: ignore burstcount to improve tpm_tis send() performance
tpm: reduce polling delay in tpm_tis wait_for_tpm_stat()
tpm: reduce tpm_msleep() time in get_burstcount()
tpm: use tpm_msleep() value as max delay

drivers/char/tpm/tpm-interface.c | 60 ----------------------
drivers/char/tpm/tpm.h | 6 +--
drivers/char/tpm/tpm_tis_core.c | 106 +++++++++++++++++++++++++++++----------
drivers/char/tpm/xen-tpmfront.c | 60 ++++++++++++++++++++++
4 files changed, 141 insertions(+), 91 deletions(-)

--
2.13.3

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