From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56534C43381 for ; Tue, 12 Mar 2019 20:56:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 21A00213A2 for ; Tue, 12 Mar 2019 20:56:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726527AbfCLU4f (ORCPT ); Tue, 12 Mar 2019 16:56:35 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:35638 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726329AbfCLU4f (ORCPT ); Tue, 12 Mar 2019 16:56:35 -0400 Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x2CKhfeT085060 for ; Tue, 12 Mar 2019 16:56:34 -0400 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0a-001b2d01.pphosted.com with ESMTP id 2r6h93t8py-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 12 Mar 2019 16:56:33 -0400 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 12 Mar 2019 20:56:27 -0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x2CKuRgD22282462 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 12 Mar 2019 20:56:27 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E12814C046; Tue, 12 Mar 2019 20:56:26 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B2FB14C04A; Tue, 12 Mar 2019 20:56:25 +0000 (GMT) Received: from localhost.localdomain (unknown [9.80.93.217]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 12 Mar 2019 20:56:25 +0000 (GMT) Subject: Re: [PATCH] tpm: Make timeout logic simpler and more robust From: Mimi Zohar To: Calvin Owens Cc: Peter Huewe , Jarkko Sakkinen , Jason Gunthorpe , Arnd Bergmann , Greg Kroah-Hartman , "linux-integrity@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Kernel Team Date: Tue, 12 Mar 2019 16:56:15 -0400 In-Reply-To: <20190312200820.GB5058@Haydn> References: <358e89ed2b766d51b5f57abf31ab7a925ac63379.1552348123.git.calvinowens@fb.com> <1552410298.24794.73.camel@linux.ibm.com> <20190312200820.GB5058@Haydn> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 (3.20.5-1.fc24) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19031220-0020-0000-0000-00000321CCEE X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19031220-0021-0000-0000-00002173FA8D Message-Id: <1552424175.24794.105.camel@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-03-12_12:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1903120140 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2019-03-12 at 20:08 +0000, Calvin Owens wrote: > On Tuesday 03/12 at 13:04 -0400, Mimi Zohar wrote: > > On Mon, 2019-03-11 at 16:54 -0700, Calvin Owens wrote: > > > We're having lots of problems with TPM commands timing out, and we're > > > seeing these problems across lots of different hardware (both v1/v2). > > > > > > I instrumented the driver to collect latency data, but I wasn't able to > > > find any specific timeout to fix: it seems like many of them are too > > > aggressive. So I tried replacing all the timeout logic with a single > > > universal long timeout, and found that makes our TPMs 100% reliable. > > > > > > Given that this timeout logic is very complex, problematic, and appears > > > to serve no real purpose, I propose simply deleting all of it. > > > > Normally before sending such a massive change like this, included in > > the bug report or patch description, there would be some indication as > > to which kernel introduced a regression. Has this always been a > > problem? Is this something new? How new? > > Honestly we've always had problems with flakiness from these devices, > but it seems to have regressed sometime between 4.11 and 4.16. Well, that's a start.  Around 4.10 is when we started noticing TPM performance issues due to the change in the kernel timer scheduling.  This resulted in commit a233a0289cf9 ("tpm: msleep() delays - replace with usleep_range() in i2c nuvoton driver"), which was upstreamed in 4.12. At the other end, James was referring to commit "424eaf910c32 tpm: reduce polling time to usecs for even finer granularity", which was introduced in 4.18. > > I wish a had a better answer for you: we need on the order of a hundred > machines to see the difference, and setting up these 100+ machine tests > is unfortunately involved enough that e.g. bisecting it just isn't > feasible :/ > What I can say for sure is that this patch makes everything much better > for us. If there's anything in particular you'd like me to test, I have > an army of machines I'm happy to put to use, let me know :) I would assume not all of your machines are the same nor have the same TPM.  Could you verify that this problem is across the board, not limited to a particular TPM. BTW, are you seeing this problem with both TPM 1.2 or 2.0? thanks! Mimi