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c=relaxed/relaxed; d=me.com; s=1a1hai; t=1788182232; x=1790774232; bh=3/beUJx10Bu3Pcl/YQ29DbawiaU1Aszo14MSQ9bHoho=; h=From:To:Subject:Date:Message-ID:MIME-Version:x-icloud-hme; b=jxg2K/yBbZQvuLhmLnRZ2jIt4eWLI9AuPsUCubAMyQhPPdzdvgiyCOhmOgLXJoWXoMpZqOGZFjSo1UBReqmOp2lUkXwzvMvghsxtQSz//8h6iog5Qr9oaMnagYyv7eygCAhHLfhLTbnbuXYyNSRhxXKRvpjR5fpRjgUp8i697871oP+n8LHM8hF7K80Sd/RXal2ANeSm6N1CaY3kJ1FqSyKda4hVTYFaPwyUpsAZoWxQi2ADVU9+PXevsJ9IgvI1gaLhwEGdDAdug4aCLNAR8jKwHWfLntDmAYwgkrruX9G3dWIIlL3S7kqB8NWQo57q12R9zD3WUdnHtbAsKKvQvw== Received: from ncore (unknown [17.156.216.30]) by p00-icloudmta-asmtp-us-east-1a-60-percent-11 (Postfix) with ESMTPSA id AB56E1800CE1; Mon, 31 Aug 2026 13:17:06 +0000 (UTC) From: Ferran Duarri To: Alexey Bogoslavsky , Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg Cc: Yehuda Hahn , linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, Ferran Duarri Subject: Re: [PATCH] nvme: lower default APST max latency to 25ms Date: Mon, 31 Aug 2026 15:17:00 +0200 Message-ID: <20260831131701.200793-1-ferran.duarri@me.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Proofpoint-GUID: igq9J5bSi09HSGx-EJA4bRPLqKQmF-UR X-Proofpoint-ORIG-GUID: igq9J5bSi09HSGx-EJA4bRPLqKQmF-UR X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODMxMDExNSBTYWx0ZWRfX4gGzkpFdGDMY SKIeY3Dst9/b6aGFqncbjSKvKoImrcKN3jGyRG2rNdoldF3yanlskXHNcl2MyEAQW/j4ON3eynu oluXRes6Gjc0GcifZj8hB+lLdrMuLlSDHhnxx8wEiqqH4PBUFXgU7AVQmdRMN7bRDqQfQsNZm+v T9uLyJoJ5nY2ZnB/TcPAbrgVky5KHeodIOAEqHrDvv0xC0aFNnUpcB5X5x2Py9SIdQoKrH74+hC zQUYiCrAMiuXirHnTdXRPtgGn/x50U9kS6o2shUtfCeBCEbimRzFr6wihAxtpxKPE5nX4XF9cWk VivjI42Eyr1tZ7X1tSqULsMFCUdwUG97wcYdCyto4YKobuGwP6/S8B4HVbNfZA= X-Authority-Info-Out: v=2.4 cv=HfsZjyE8 c=1 sm=1 tr=0 ts=6a957ed6 cx=c_apl:c_pps:t_out a=oyWFxbOnq+dmhQrAPgaJYA==:117 a=oyWFxbOnq+dmhQrAPgaJYA==:17 a=Sv0fKeRqtYgA:10 a=x7bEGLp0ZPQA:10 a=B9nqV3Rn1-QA:10 a=VkNPw1HP01LnGYTKEx00:22 a=8FC1iW-_3rLwuDBYcQIA:9 X-JNJ: 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 QXIO54y1kmICSsYLcmKYjTPH6N53UJSyxxSQwnpwhYxIDweictnG7/CKfWWhbgvHsYQF65rVdZOgdCVFJoCncSdpzjWncWI6drOXiwAXwEi5+e5U+rtcdaDH6Yw9CkpbqSWXR5yBjO8pMaTrX0i2/0Mkyl2/YSNXKlT74JUr8ktFzrJiuZXyvZ6p+Wk42l32ysDGlA4hDwk4JMgOnXMmktZqiyg/3ShJnTyhuBOosd3OYNjjuJ6/DB3Ekd67PItrF98xeJUNo2s6jqj14eGSCzltTGeDsPYwN3PHZq08= X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260831_061716_365118_27F29CA9 X-CRM114-Status: GOOD ( 11.15 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org Alexey - thanks, that's a real point I hadn't considered: if EXLAT is deliberately inflated to keep Windows on ps3, the 100ms default isn't a bug, it's aligned with what vendors actually tuned for. The measurement itself I think still holds - it's reading what the drive's live APST table targets, not just trusting the label, and the wake cost at ps4 was real regardless of why 43ms is the number on the tin. But that's a different question from whether Linux should default away from it. What's the OEM precedent you mentioned - did lowering the bound before break something specific, or was it more general pushback? Trying to understand if this needs to stay a boot-time opt-in (which it already is via default_ps_max_latency_us) rather than ever being a compiled default, on any hardware. Also - sorry for the fourth copy of this patch landing in your inbox on the 28th. That was a bookkeeping failure on my end, not a deliberate re-post; it went out after your reply had already arrived and should not have. Cheers, Ferran