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charset=us-ascii Content-Disposition: inline In-Reply-To: <20250206142234.-kcSg0xr@linutronix.de> X-Rspamd-Queue-Id: 3365280022 X-Stat-Signature: 795kkq3aw6km6kxjn9iedwau6t6p3j98 X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1738853502-610041 X-HE-Meta: U2FsdGVkX1/MAEEIv7VwTb0Ae8cvK2PXg9RUhZ5Pm8L7zwSxLiceZq3jYuNFHtBlAlJTyTtqu78gdUyDqvEW4OxqqnW0RpGIQunoMcciSHk2xXpiwEHAKB9uQok9wpJTQHy3WrIMcVbfIRNjFSbY1XJyXwP44UC8Ipck7F2our+c2dn/CwVOY+ux7JeN4LJjSZU1Rl7v0CvaKNNmDWLtgmGgID0W3OKvwpN5SVDVe3c3TxkbUOxX7xpqQrHgKhp96ICDY2stDEzPg6zQCCqfjPl2M/OMHnfft5q117R40VF54/qOIcstS5Ko9xEKl/wn7pSEEb6Od9lMCQGMAsHi9nlhpqS6DtDl35q8yQDzjxCZPXwmcddrlZEtTKFkyADudKTFZK+H3kThTJU3qRzWphyiKyAuBgkUCgTMLLsousaBHIMmvupSCU/cH55vT0Of8DsMat60IxmjEiLtHnJt+IlMvzB5AMil1ZWvkEZh9FBze7kfSRS3/OFhpqWbWcHU407u0OLRriBCHz0G1Eh9kbVKDduxSCDAZcqTTS3ZEQjUbzlfmBlOyjs9RjV9fTsBcDBv5c/QUeaBmfmZWafUa9HfbpxB0p52DOdfFoKERnvKuDXfhkhYfNrsffvSr83qpezQ72fjDHHjU6STajAkyq0NBoKrqNQAuGztsDLdLcruNTPBQStdJaHuO8SPsP9kN8IBbLCTIbbNtfuFF0LLjrWvE/a82I+707Y0XKNgvypnSJMhIlgOUywweNJ7QmhOL++3/pppxDC9E45CAR8boTSk6L/bWMWCdBEk6fHUV5Wc2XgzT2exayj6tBV2xOXPaddoYTz2MrAiqjgvssaVkIwom731DhbwxcC+ozZCPaP0q7QB7BNq+a25R4ETvdmEiXowXbVBl1dxbBfepdWIP98I89uGpshUlSkCKp/dXO9oWb9PHZZbfnrEul+AUJJNxs0uJSbydp5/mcHKvf0 rJaOyKFd wyHtp4zm/q5U5QnKhAyn+8pEiDrKyUiKa2k9lIhav4nB47Is0VA2vv/UbJx5t2v90Y6HEr4n0TDEvGE7AiBogbf7OBjrTHyxcn6hFVvih0lTKWqXLIwoLW5Dt4DtuHKrY5Xcq9ms0/bCLqNFrMyklI2WJvKn9bj1cZe6oXm3OoOzLxX/87pGUIIVL8Un9bk/n1LDZqYNHLPLe/mBbozdpkXzLPMiNgNZHUZMyOXhPM2Zpzln0DzX/p+ikOQF0NrPjkfcbZfyWBOv0RWc= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Feb 06, 2025 at 03:22:34PM +0100, Sebastian Andrzej Siewior wrote: > Then this feature adds 20us on top? The point has always been for the number to be < the observable scheduling latency. I'm not sure what that number is, and it is always hardware dependent. I measured it on a random test box when I did the prototype a long while ago, and ended up at 50us, but for all I know that machine was running a lockdep enabled kernel at the time (won't be the first and certainly won't be the last time I try and do a performance measurement on a debug kernel). That was not the important part -- but everybody fixates on the number, instead of the intent. I'm assuming you have a recent number around -- what's sane? 5us, less?