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[24.1.27.177]) by smtp.gmail.com with ESMTPSA id d13-20020ac8534d000000b00429bc01acc5sm4490445qto.68.2024.01.24.09.15.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 24 Jan 2024 09:15:35 -0800 (PST) Date: Wed, 24 Jan 2024 11:15:32 -0600 From: David Vernet To: Joel Fernandes Cc: bpf@vger.kernel.org, lsf-pc@lists.linux-foundation.org, Sean Christopherson , Vineeth Pillai , Steven Rostedt , Suleiman Souhlal Subject: Re: [LSF/MM/BPF TOPIC] Implementing KVM vCPU Priority boosting via BPF Message-ID: <20240124171532.GB253330@maniforge> References: <653c2448-614e-48d6-af31-c5920d688f3e@joelfernandes.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="iVw72lHJuzBnWXgd" Content-Disposition: inline In-Reply-To: <653c2448-614e-48d6-af31-c5920d688f3e@joelfernandes.org> User-Agent: Mutt/2.2.12 (2023-09-09) --iVw72lHJuzBnWXgd Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jan 23, 2024 at 09:59:50PM -0500, Joel Fernandes wrote: > We should discuss a new approach for increasing KVM virtual CPU (vCPU) pr= iority > when guests need low latency. The last RFC posting [1] on this is thought= to be > too rigid and baking too much policy into the kernel. Incorporating compl= ex > policy logic directly into KVM seems problematic long-term for maintenanc= e. Lets > discuss leveraging BPF programs to offload more scheduling policy decisio= ns to > BPF / userspace. >=20 > Specific issues to discuss: >=20 > * Add support for enabling BPF programs to share memory and interface wit= h guest. >=20 > * Create a kernel function allowing BPF programs to call sched_setschedul= er(), > facilitating priority boosting. >=20 > * UAPI concerns. >=20 > * Challenges with loading BPF programs in guest userspace we don't contro= l. >=20 > [1] https://lore.kernel.org/all/20231214024727.3503870-1-vineeth@bitbytew= ord.org/ +1 to discussing all of the above at LSFMM, ideally as part of the BPF track. --iVw72lHJuzBnWXgd Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEARYKAB0WIQRBxU1So5MTLwphjdFZ5LhpZcTzZAUCZbFFtAAKCRBZ5LhpZcTz ZNQrAQCVm9P/M2rC7rEK15ADkaBylmfJhtDVSBtXETyRsr4gtgEAt+RdoBZ5uexP y5fCGBIC30MoNBoMAFDNjEvHtorymwg= =WZqK -----END PGP SIGNATURE----- --iVw72lHJuzBnWXgd--