From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793942096; b=M2LDHrzq9xQjNZz/o3E6gorhlgNLXICihp3799RLy/wwDMMIfVGAT0cHziH+mtzzrJ35 /ArbBYqZbrrisasPTC37pGCB3A1uJOeNV/xPO5/9ECgKmWCSQSN+0yZnJkN7cONYaobGH AU/orvuoWer7IyexsZjOifUPsiJMGR4bJETQu/eZOi6RvaAlzZcTY2wiO98skX0sLe+zO QfuREx1QUT3sBdlb1IReBgj/nCIDsCXQHylIKuGLNaMFusnds4u+oFTIqVA5yNsO8RvbC s2QtujTx+Sv88Sc48xOIr1XncYaxVH4G9R44GLOyWUTvQxPE3iiRsF1qooy86Z8e0Tw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793942096; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=clSnnLV1EvdVPl5f7/JwDfbig6rIdyUSMbJBacuaHF0=; b=CUC1DwZEmkjP1DwHTZEG0M8fpw7yacHK+WEIqtb+9XhTuqKWz7PiI4qNRPBOb7a2SKVP zqbtEVQsvGf45vrJxHUgi5R5ESEWkIAazrvrxzc4jdkk6v3D2fEDjrjAuhDcRaA2YlQRk qMN9CGGCfCZwGUi2wpxipQiPo1b0AM1Hu48kmeGWix05dXQSzGnhxSOszHaaEjjenYRbz erLDJ+2Bf7Uz0/fB5u3Y13R0hcMrleA53Joq84rmpCmbhWNNJqAPrZVH9u+eWzNUZnlqf ExvZ/dr08JFrylqKC6fpe7YCvU4jrLQeGZ9nx7vVtuhiU79Dbrq76w4nVu5vP8AnL1Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=DPIzMGdi; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 366CE606A31B for ; Fri, 6 Nov 2026 05:14:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=DPIzMGdi Received: by smtp.kernel.org (Postfix) with ESMTPSA id A3C201F0089F; Fri, 6 Nov 2026 05:14:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793942095; bh=clSnnLV1EvdVPl5f7/JwDfbig6rIdyUSMbJBacuaHF0=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=DPIzMGdiyvEDvkijy8Sr95DqZBTxPTLRY1NA31A+uBZwbwiPkEFJ3We2tbv02jtkQ lSu66srqgkkJqnk3Hnk7KcHOyYG+2wceorEPw0P62wMHpthrFat+vhx6e5HlufbHZL p9PGRN6pF57nGdjkMnCtGRG0AEd/0wXcL5cISlYmmIY8ROVohJHay78/rqEYCa3mS9 d3pt/h6XNGhXobRMLZMojPFmszAnW1lIIXdWEUOGJxsbNXzcEY2jOcxA2c7U3IoYbT lCnay5n/CIiFxgiqhXX3F66t2Fzk+tnHWnJoiYo22z00lyP86RqqYLixSiWfn5yMTN Iv9JKYdU8MZ0g== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v7 13/14] alpha/perf: sample only retired instructions for precise events Reply-To: sashiko-reviews@lists.linux.dev To: "Matt Turner" Cc: linux-perf-users@vger.kernel.org In-Reply-To: <20261105-alpha-profileme-v7-13-c474e892abb0@gmail.com> References: <20261105-alpha-profileme-v7-0-c474e892abb0@gmail.com> <20261105-alpha-profileme-v7-13-c474e892abb0@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 06 Nov 2026 05:14:55 +0000 X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > ProfileMe samples include instructions killed on a wrong path, which > show up as hot spots in perf report although they did no work. On an > EV7 loop with a randomly mispredicted branch, 19% of the samples were > killed before being mapped and another 48% later. >=20 > PEBS and AMD IBS op samples are of retired instructions only, so make > precise_ip imply the retired filter, unless filters are given. The > profileme bit still selects every sample. With cycles:p, both kinds of > killed sample went to 0%. >=20 > DTB miss samples, whose instruction is aborted, are then dropped too: > cycles:p reports DTB hits only, and the misses need cpu/cycles,trapped/p. >=20 > The kept samples carry the full period, as do those AMD IBS keeps when > its swfilt discards others. So in frequency mode the sample rate, and > the event count perf report estimates from the periods, fall by the > share of killed instructions: to about a third on that loop. >=20 > Suggested-by: Ian Rogers > Assisted-by: Claude:claude-opus-5-5 > Reviewed-by: Magnus Lindholm > Tested-by: Magnus Lindholm > Signed-off-by: Matt Turner Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261105-alpha-prof= ileme-v7-0-c474e892abb0@gmail.com?part=3D13