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Wed, 24 Apr 2019 18:47:53 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x3OIlqKP096692; Wed, 24 Apr 2019 18:47:52 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3030.oracle.com with ESMTP id 2s0f0w87th-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 24 Apr 2019 18:47:52 +0000 Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x3OIlonq000790; Wed, 24 Apr 2019 18:47:51 GMT Received: from bostrovs-us.us.oracle.com (/10.152.32.65) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 24 Apr 2019 11:47:50 -0700 Subject: Re: [PATCH] x86/xen: Add "xen_timer_slop" command line option To: thibodux@gmail.com, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Cc: oleksandr_andrushchenko@epam.com, tglx@linutronix.de, jgross@suse.com, ryan.thibodeaux@starlab.io References: <1553279397-130201-1-git-send-email-ryan.thibodeaux@starlab.io> From: Boris Ostrovsky Openpgp: preference=signencrypt Autocrypt: addr=boris.ostrovsky@oracle.com; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <1553279397-130201-1-git-send-email-ryan.thibodeaux@starlab.io> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9237 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904240135 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9237 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default 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-1904240134 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/22/19 2:29 PM, thibodux@gmail.com wrote: > From: Ryan Thibodeaux > > Add a new command-line option "xen_timer_slop=" that sets the > minimum delta of virtual Xen timers. This commit does not change the > default timer slop value for virtual Xen timers. > > Lowering the timer slop value should improve the accuracy of virtual > timers (e.g., better process dispatch latency), but it will likely > increase the number of virtual timer interrupts (relative to the > original slop setting). > > The original timer slop value has not changed since the introduction > of the Xen-aware Linux kernel code. This commit provides users an > opportunity to tune timer performance given the refinements to > hardware and the Xen event channel processing. It also mirrors > a feature in the Xen hypervisor - the "timer_slop" Xen command line > option. > > Signed-off-by: Ryan Thibodeaux Applied to for-linus-5.2