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Tue, 24 Feb 2026 15:45:01 -0800 (PST) Received: from Cumhall ([142.189.59.50]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8cb8d0468cbsm1040509785a.4.2026.02.24.15.45.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Feb 2026 15:45:01 -0800 (PST) Date: Tue, 24 Feb 2026 18:44:59 -0500 (EST) From: John Kacur To: Costa Shulyupin cc: linux-rt-users , Bart Wensley , John Kacur , Clark Williams Subject: Re: [PATCH v3] rt-tests: hwlatdetect: Add MTBF calculation In-Reply-To: <20260220182428.75379-2-costa.shul@redhat.com> Message-ID: References: <20260220182428.75379-2-costa.shul@redhat.com> Precedence: bulk X-Mailing-List: linux-rt-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII On Fri, 20 Feb 2026, Costa Shulyupin wrote: 8< ----------- > > + if exceeding > 1: > + info(f"MTBF: {(float(detect.last) - float(detect.first)) / (exceeding - 1):.3f} seconds") > + With newer kernels you can get multiple latency events ie, the count per timestamp but you don't know when they occurred. (the timestamp measures the occurence of the first event) Does it therefore make more sense to measure the mean time between samples (distinct timestamp entries) Does the following make more sense? if detect.samples > 1: info(f"MTBF: {(float(detect.last) - float(detect.first)) / (len(detect.samples) - 1):.3f} seconds") > if detect.have_msr: > finishsmi = detect.getsmicounts() > total_smis = 0 > -- John