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Wed, 25 Feb 2026 09:56:30 +0000 (GMT) Message-ID: <577cbf87-277a-4c6c-802f-00096c788036@linux.ibm.com> Date: Wed, 25 Feb 2026 09:56:29 +0000 Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] sched: Further restrict the preemption modes To: Sebastian Andrzej Siewior Cc: Peter Zijlstra , mingo@kernel.org, Thomas Gleixner , juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, clrkwllms@kernel.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, Linus Torvalds , linux-s390@vger.kernel.org References: <20251219101502.GB1132199@noisy.programming.kicks-ass.net> <182f110b-ac63-4db4-8b01-0e841639bc39@linux.ibm.com> <20260224171111.pMPZGcan@linutronix.de> Content-Language: en-GB From: Ciunas Bennett In-Reply-To: <20260224171111.pMPZGcan@linutronix.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-ORIG-GUID: ggHshAP3UyibOZyxBiXtLS-kZivmJKZu X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMjI1MDA5NCBTYWx0ZWRfX0MbjVq7t+wi3 6zdy+FZeEgMGKB1KxjX0sPy8FNQ9/VpU2wLzRKEFKJw93j4/VawIGTWIsmUsa7PY7XKqR/cQYVR E8zXF3NjoJGsp5nlUuTwE1DALmRweDnTugiMftniuxl82V6KY+inyjQbCc+dxl8w8WgWs9r4m/d PPWUum0gUrOqWgzT0uPDCsmKTf1hQEGyx7XqRZyMjcJgzPhbnSCKbqhiW/A4gnZG6p5/4PAnd9u kAiIksHMxdMb5inu3saoAhfTew180tB+9dG5dtAiIVSvmhAHfjNwGZR8nWeCtEKsypJBnkNbZyd rlbuPYW/SzwHPUAk/jXyLzIxkb86Z8PlGW2zqJv2+rlIB6TdI8btTCdD6l4BNETn+3MJ9Xiu21G eqozPPm7PiejJSMbdLze34zuRbEF1MtEyj267DgHFOOXP8njhKIfrvrgfLrfWxMJ4Wi66poMKmN TECSe/ft1FdvoWByUHg== X-Proofpoint-GUID: ywS_kq-zX7Bgtpvgm1LejcIjFR0T7asY X-Authority-Analysis: v=2.4 cv=bbBmkePB c=1 sm=1 tr=0 ts=699ec752 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=HzLeVaNsDn8A:10 a=VkNPw1HP01LnGYTKEx00:22 a=Mpw57Om8IfrbqaoTuvik:22 a=GgsMoib0sEa3-_RKJdDe:22 a=315T5f-plpDpaHdBaGwA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-02-24_03,2026-02-23_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 bulkscore=0 adultscore=0 impostorscore=0 lowpriorityscore=0 priorityscore=1501 suspectscore=0 clxscore=1015 phishscore=0 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2601150000 definitions=main-2602250094 On 24/02/2026 17:11, Sebastian Andrzej Siewior wrote: > On 2026-02-24 15:45:39 [+0000], Ciunas Bennett wrote: >> Changing guest configuration to disable mergeable RX buffers: >> >> had a clear effect on throughput: >> PREEMPT_LAZY: throughput improved from 40 Gb/s → 60 Gb/s >> > > Brings this the workload/ test to PREEMPT_FULL level? > Sorry was not clear here, so when I enable this there is also an improvement in PREEMPT_FULL from 55Gb/s -> 60Gb/s So I see an improvement in both test cases. PREEMPT_LAZY: throughput improved from 40 Gb/s → 60 Gb/s PREEMPT_FULL: throughput improved from 55 Gb/s → 60 Gb/s