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Wysocki" , Daniel Lezcano , Anna-Maria Behnsen , Frederic Weisbecker , Ingo Molnar , Thomas Gleixner Cc: Ilya Leoshkevich , Christian Borntraeger , linux-s390 , linux-kernel References: <20260609075213.31094-1-meted@linux.ibm.com> <20260609075213.31094-2-meted@linux.ibm.com> <7d2ace86-f355-4ff7-886b-7963574b2202@linux.ibm.com> Content-Language: en-US From: Mete Durlu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: ok-1e1Ow2uwaSa8MahSe4DsAiIm2Mree X-Proofpoint-GUID: ok-1e1Ow2uwaSa8MahSe4DsAiIm2Mree X-Authority-Analysis: v=2.4 cv=ZbEt8MVA c=1 sm=1 tr=0 ts=6a27e51d cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=IkcTkHD0fZMA:10 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=h0VFYf4W8FCvH31RdjUA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjA5MDA4OSBTYWx0ZWRfX2q7VL4hZEJBX uSC0An5UBOdEsNEabcarzg3EeaWSToPII2BpfcoFDSVpSuwXInGtF6Co8yl1p2ubhGbpXeC84Ux APCFXI1JwlNxT2sPB0PnzQJabJQBuODRmnTSh9AXk34qLHpoNWmqWxSpyZwtGqYTSMM6m2dFKQy cIelriN8/xocAnvkBR4nASDgpTgE511q2p2VfV6nxa+e/GfiLroVC0d0kq9kizqD9ARYEW/Rsai WLAeIUYalky49FxnqbWHeha8hHI8GajUWpGeV63mFoH27zRTAHn4CPczG9xel8xcN1vDfV2U25a vSDd9ponuH38CiN8B+4RqC/hQ0/iItMVyxg5toDgeBQYCWVE7HPlLvTnCIrjbC9oQJKNKSsPOZf 2GtKkQyjTgNlkZuF1daxb+NFoZvZGfbswuY7mpc5mDsMvbwGoW1WcUnI82+iME6T2JN12ofOMpy lK74Kf843/LRHVPXTng== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-09_02,2026-06-09_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 impostorscore=0 malwarescore=0 lowpriorityscore=0 clxscore=1015 adultscore=0 spamscore=0 priorityscore=1501 bulkscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2605210000 definitions=main-2606090089 On 6/9/26 11:52, Christian Loehle wrote: > On 6/9/26 10:40, Mete Durlu wrote: >> On 6/9/26 10:10, Christian Loehle wrote: >>> On 6/9/26 08:52, Mete Durlu wrote: >>>> Remove obsolete tick delay heuristic [1]. The upcoming cpuidle driver >>>> handles frequent sleep/wakeup cycles more effectively. >>>> >>>> [1] https://lore.kernel.org/all/20090929122533.402715150@de.ibm.com/ >>>> >>>> Suggested-by: Heiko Carstens >>>> Signed-off-by: Mete Durlu >>>> --- >>> For bisectibility does it make sense to move this and 2/5 to the end? >> >> I am unable to see how that would help. Could you elaborate? > > CIF_NOHZ_DELAY is only obsolete because of the new s390 cpuidle driver > handles NOHZ better overall right? > So my suggestion was to only obsolete it once everything is in place? CIF_NOHZ_DELAY could modify the idle driver's decisions when it comes to disabling the scheduling tick. It could be hard to bisect a problem with the driver if we move the removal of the flag after the drivers introduction. Because then the commit that enables the driver can have a significantly different behavior. Plus,having the flag obsolete without any other mechanism doing a similar job would make the effect and related behavior more visible and easier to debug. At least this is my opinion but I am not an expert in kernel bisecting tbh.