On Wed, Sep 06, 2017 at 08:56:35AM -0400, Nayna Jain wrote: > After further discussions with the 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 during send() 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: define __wait_for_tpm_stat to specify | ~14 - ~10 > variable polling sleep time > > tpm: reduce tpm_msleep() time in | ~10 - ~9 > get_burstcount() > > tpm: modify tpm_msleep() function to have | ~9 - ~8 > max range > > 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 (4): > tpm: ignore burstcount to improve tpm_tis send() performance. > tpm: define __wait_for_tpm_stat to specify variable polling sleep time > tpm: reduce tpm_msleep() time in get_burstcount() > tpm: use tpm_msleep() value as max delay > > Documentation/admin-guide/kernel-parameters.txt | 8 ++++++ > drivers/char/tpm/tpm-interface.c | 15 ++++++++-- > drivers/char/tpm/tpm.h | 7 +++-- > drivers/char/tpm/tpm_tis_core.c | 37 > +++++++++++++++++++------ > 4 files changed, 53 insertions(+), 14 deletions(-) > > -- > 2.13.3 >
I'll look into this after next week. /Jarkko
