From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933582AbeB1TS4 (ORCPT ); Wed, 28 Feb 2018 14:18:56 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:39582 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932780AbeB1TSx (ORCPT ); Wed, 28 Feb 2018 14:18:53 -0500 From: Nayna Jain To: linux-integrity@vger.kernel.org Cc: zohar@linux.vnet.ibm.com, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, peterhuewe@gmx.de, jarkko.sakkinen@linux.intel.com, tpmdd@selhorst.net, jgunthorpe@obsidianresearch.com, patrickc@us.ibm.com, Nayna Jain Subject: [PATCH 2/3] tpm: reduce poll sleep time between send() and recv() in tpm_transmit() Date: Wed, 28 Feb 2018 14:18:27 -0500 X-Mailer: git-send-email 2.13.3 In-Reply-To: <20180228191828.20056-1-nayna@linux.vnet.ibm.com> References: <20180228191828.20056-1-nayna@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18022819-0040-0000-0000-000004191E60 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18022819-0041-0000-0000-0000261C1F6A Message-Id: <20180228191828.20056-2-nayna@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-02-28_11:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1802280234 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In tpm_transmit, after send(), the code checks for status in a loop with polling every 5msec. It is expected that the tpm might return earlier than 5msec, so it might be adding to unnecessary delay. This patch reduces the polling sleep time from 5msec to 1msec. After this change, performance on a TPM 1.2 with an 8 byte burstcount for 1000 extends improved from ~14sec to ~10.7sec. Signed-off-by: Nayna Jain --- drivers/char/tpm/tpm-interface.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c index 76df4fbcf089..2d22f981f0c9 100644 --- a/drivers/char/tpm/tpm-interface.c +++ b/drivers/char/tpm/tpm-interface.c @@ -470,7 +470,7 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space, goto out; } - tpm_msleep(TPM_TIMEOUT); + tpm_msleep(TPM_TIMEOUT_POLL); rmb(); } while (time_before(jiffies, stop)); -- 2.13.3