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Peter Anvin" , "Peter Zijlstra (Intel)" , Ilpo =?iso-8859-1?Q?J=E4rvinen?= , Marco Elver , "Guilherme G. Piccoli" , Nikunj A Dadhania , "Xin Li (Intel)" , Dimitri Sivanich Subject: [PATCH v4 0/2] x86/tsc: Exempt recent UV systems from clocksource watchdog checks to avoid false positives. Message-ID: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Authority-Analysis: v=2.4 cv=K+8S2SWI c=1 sm=1 tr=0 ts=6a0f05e5 cx=c_pps a=FAnPgvRYq/vnBSvlTDCQOQ==:117 a=FAnPgvRYq/vnBSvlTDCQOQ==:17 a=kj9zAlcOel0A:10 a=NGcC8JguVDcA:10 a=VkNPw1HP01LnGYTKEx00:22 a=gQcMVamqm3wCPoSYhaRC:22 a=6XKncaru_qjgLvANlS_8:22 a=KxLUGFj1uHtzeumYTaAA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-ORIG-GUID: pqieCHPngZf64Zu7pq1WWbDaVz_1rAFG X-Proofpoint-GUID: pqieCHPngZf64Zu7pq1WWbDaVz_1rAFG X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNTIxMDEzMyBTYWx0ZWRfX7qwIM1Ae+AP5 VV/CymfNB2vMKsxr+O2reufsqJUnsAxkfh30ror2Q9j+I9OGkvQLvZ4/wwU98NAM/aEAWXI0T78 tdI1ZXbqrgFYE4dlJuPBJCXqWvWZ+WXLeED6FJzy6R6ZVO9ggR7S8eaD5uoMWvGqMXk1+LnEwRS OD9CEb1Zhzqhyzkizjvv9O+wGXKZoNB3W70HeR1Kc+dSL3lS7egXrDuHQiQOwmCRVT8EzQq7Nr2 STvUTEnVD4Eq0wfeitKiZX+fSZVda+k5U0MPcVo/P5+uu77pBEpH2ThM/QUEJmBPExWtrSYoxd3 4iCLa7yAQPl+mhc3JaBs2WdwmqJhfZN0c7ESFB1bcXa9ZxnaehP52RotGk4q2Shekwvh6eKL5eE wKPFwTut+ipYmzGdwhGClmb3IJFRlQoUgeUmJnXZQoWuJxs1sJcZjpuPFGnqNmfIM+wKLkky1Vt OzMO3Vj0kIHa3orRFpA== X-HPE-SCL: -1 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-05-21_02,2026-05-18_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 priorityscore=1501 spamscore=0 lowpriorityscore=0 suspectscore=0 phishscore=0 impostorscore=0 clxscore=1015 adultscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2605130000 definitions=main-2605210133 HPE UV hardware and firmware is designed to ensure a reliable and synchronized TSC mechanism. Comparing the TSC against secondary clocksources can result in false positives due to variable access latency caused by system traffic. The best course of action against these false positives has been found to simply disable watchdog checking of the TSC. Commits [1] and [2] were introduced to avoid an issue where the TSC is falsely declared unstable by exempting qualified platforms of up to 4-sockets from TSC clocksource watchdog checking. Extend that exemption to include recent and future UV platforms. [1] commit b50db7095fe0 ("x86/tsc: Disable clocksource watchdog for TSC on qualified platorms") [2] commit 233756a640be ("x86/tsc: Extend watchdog check exemption to 4-Sockets platform") Dimitri Sivanich (2): Expose the uv_hub_type() interface Disable clocksource watchdog checking on recent and future UV platforms. arch/x86/include/asm/uv/uv_hub.h | 7 +++++++ arch/x86/kernel/tsc.c | 27 +++++++++++++++++++++------ 2 files changed, 28 insertions(+), 6 deletions(-) -- 2.43.0