From mboxrd@z Thu Jan 1 00:00:00 1970 From: jarkko.sakkinen@linux.intel.com (Jarkko Sakkinen) Date: Tue, 12 Sep 2017 18:00:11 -0700 Subject: [PATCH v2 3/4] tpm: reduce tpm_msleep() time in get_burstcount() In-Reply-To: <20170906125643.5070-4-nayna@linux.vnet.ibm.com> References: <20170906125643.5070-1-nayna@linux.vnet.ibm.com> <20170906125643.5070-4-nayna@linux.vnet.ibm.com> Message-ID: <20170913010011.myvhrj2f4i3piphl@linux.intel.com> To: linux-security-module@vger.kernel.org List-Id: linux-security-module.vger.kernel.org On Wed, Sep 06, 2017 at 08:56:38AM -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 5 msec 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 > Acked-by: Mimi Zohar > --- > 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 d1eab29cb447..d710bbc4608b 100644 > --- a/drivers/char/tpm/tpm_tis_core.c > +++ b/drivers/char/tpm/tpm_tis_core.c > @@ -169,7 +169,7 @@ static int get_burstcount(struct tpm_chip *chip) > burstcnt = (value >> 8) & 0xFFFF; > if (burstcnt) > return burstcnt; > - tpm_msleep(TPM_TIMEOUT); > + tpm_msleep(1); > } while (time_before(jiffies, stop)); > return -EBUSY; > } > -- > 2.13.3 How did you pick 1 ms delay? Should there be a constant defining it? /Jarkko -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html