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Fri, 31 Jul 2026 14:41:38 -0700 (PDT) Date: Fri, 31 Jul 2026 14:41:37 -0700 In-Reply-To: Mime-Version: 1.0 References: <20260731195612.2697986-1-seanjc@google.com> Message-ID: Subject: Re: [PATCH v3 00/12] KVM: selftests: Add more syscall wrappers, fix hardware_disable_test From: Sean Christopherson To: Yosry Ahmed Cc: Paolo Bonzini , Marc Zyngier , Oliver Upton , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Joey Gouly , Steffen Eiden , Suzuki K Poulose , Zenghui Yu , David Hildenbrand , kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260731_144140_566014_7139FECB X-CRM114-Status: GOOD ( 13.29 ) X-BeenThere: linux-arm-kernel@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-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Jul 31, 2026, Yosry Ahmed wrote: > On Fri, Jul 31, 2026 at 12:56=E2=80=AFPM Sean Christopherson wrote: > > > > Third time's a charm. Sorry for the spam. > > > > Buried in the middle of this is a fix for the hardware_disable_test whe= re > > it can end up with a runtime of multiple minutes when running a preempt= ible > > kernels on a large NUMA system. Turns out my analysis/guess in v1 was = wrong; > > the problem isn't direct CPU contention, it's that letting the workers = do any > > amount of "real" work on any CPUs leads to pthread_create() slowdowns f= rom > > the perspective of the caller. >=20 > How long does the test take to run with this series? Less than 5 seconds if nothing else is running. ~12 seconds if I run it concurrently with mmu_stress_test using default settings, and ~25 seconds i= f I run it on an overloaded system (naively running all selftests in parallel).