Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754225AbdIFM52 (ORCPT ); Wed, 6 Sep 2017 08:57:28 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:45943 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754143AbdIFM5Z (ORCPT ); Wed, 6 Sep 2017 08:57:25 -0400 From: Nayna Jain To: tpmdd-devel@lists.sourceforge.net Cc: peterhuewe@gmx.de, tpmdd@selhorst.net, jarkko.sakkinen@linux.intel.com, jgunthorpe@obsidianresearch.com, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ima-devel@lists.sourceforge.net, patrickc@us.ibm.com, Nayna Jain Subject: [PATCH v2 3/4] tpm: reduce tpm_msleep() time in get_burstcount() Date: Wed, 6 Sep 2017 08:56:38 -0400 X-Mailer: git-send-email 2.13.3 In-Reply-To: <20170906125643.5070-1-nayna@linux.vnet.ibm.com> References: <20170906125643.5070-1-nayna@linux.vnet.ibm.com> X-TM-AS-MML: disable x-cbid: 17090612-0044-0000-0000-00000284E94B X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17090612-0045-0000-0000-000007188449 Message-Id: <20170906125643.5070-4-nayna@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-09-06_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=5 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1709060179 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1037 Lines: 31 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