| Message ID | 20171004102924.12355-4-nayna@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Oct 04, 2017 at 06:29:22AM -0400, Nayna Jain wrote: > The existing wait_for_tpm_stat() polls for the chip status after > 5msec sleep. As per TCG ddwg input, it is expected that tpm might > return status in few usec. So, reducing the delay in polling to > 1msec. > > After this change, performance on a TPM 1.2 with an 8 byte > burstcount for 1000 extends improved from ~14sec to ~10sec. > > Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com> > --- > drivers/char/tpm/tpm_tis_core.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > index 8da425e1783f..224842e06105 100644 > --- a/drivers/char/tpm/tpm_tis_core.c > +++ b/drivers/char/tpm/tpm_tis_core.c > @@ -31,6 +31,8 @@ > #include "tpm.h" > #include "tpm_tis_core.h" > > +#define TPM_POLL_SLEEP 1 Should have a comment above that explains the choice. > + > static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask, > bool check_cancel, bool *canceled) > { > @@ -82,7 +84,7 @@ static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask, > } > } else { > do { > - tpm_msleep(TPM_TIMEOUT); > + tpm_msleep(TPM_POLL_SLEEP); > status = chip->ops->status(chip); > if ((status & mask) == mask) > return 0; > -- > 2.13.3 > /Jarkko -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index 8da425e1783f..224842e06105 100644 --- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -31,6 +31,8 @@ #include "tpm.h" #include "tpm_tis_core.h" +#define TPM_POLL_SLEEP 1 + static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask, bool check_cancel, bool *canceled) { @@ -82,7 +84,7 @@ static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask, } } else { do { - tpm_msleep(TPM_TIMEOUT); + tpm_msleep(TPM_POLL_SLEEP); status = chip->ops->status(chip); if ((status & mask) == mask) return 0;
The existing wait_for_tpm_stat() polls for the chip status after 5msec sleep. As per TCG ddwg input, it is expected that tpm might return status in few usec. So, reducing the delay in polling to 1msec. After this change, performance on a TPM 1.2 with an 8 byte burstcount for 1000 extends improved from ~14sec to ~10sec. Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com> --- drivers/char/tpm/tpm_tis_core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)