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=1793676363; b=MmT5+tJpWiZFQSyX5gq0hoYpmINOtsK5bxZkB1I+wsTZsBe6Aeuyqrnn8k7KbcrtZN64 ejT5OX7QF7nnAZMrvECIIt8JbMhJmrzQEEOLaXftsKyYIcFh3wyW0xjKJdpFfJd7pKpnu Mk3fOCQLGnmt+bGDVbiwPvCNFOKgjfPWFE5zJVt4+dyhS7ReNARnH18rGTHyIFMD/vLQm JZtB+b3VcrZ4/QF+nlttBcjspr9WPIliNGAzAlCeXntVGWypZg7rrwQraZyXELfbi7CDj kBj5VBu/nS2UiMW9iPylDcFAcWJGQ0gjLAjYVexsUFR2u8dJ5wB61B5nU0+zLhEXAZg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793676363; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=4uSPJ2+TlTP5w8f8wQNSzFeQ6nkvhIU5NxcZXvOyMkU=; b=5oKE2g6OTKyUnkxCnwkcNnE/QfMa+RA018G0uqmLbLfKglvE5Gj61YuBZXPNgMpdz4Gc Dq7002rBrqpJChCtqh2w6CtKZ/ZTIjVMaC0yh9O+aAKnIKGUiztpipEPg64vz6l0RIHHw WmBBoRsYsXXMeRawMia7mxtFTWlk2gSunFvayiLB4aWVhcTlXlhXWB9pcR7/YiI7ryJbe mS3FiXRjf7J7s6gS7w26lu0oMB//Qepg9LhPwxNZc+V+32rkUHq+gPo/cj8HO7ucaPPv6 2uegyGy/IJoZmrEBSWADSCE5HqYGK4tP684PaD5MbCo8MOpeug/ObkNN4Ogjgywo9pA== 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=TudFlD92; 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 3CF78606A324 for ; Tue, 3 Nov 2026 03:26:02 +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=TudFlD92 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48A261F000C1; Tue, 3 Nov 2026 03:26:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793676362; bh=4uSPJ2+TlTP5w8f8wQNSzFeQ6nkvhIU5NxcZXvOyMkU=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=TudFlD92Uy9R6+0JA9ers743fY0Ggui0Tk4/FPAp9CHC/ErSyokv4hztaWs3OgMsE QFENEsnnpeGOH2MBaRtpCidFiTUpz22Q7Jz6J0GuGk9tobKFytc+1nuzBK4PEZ5FBn Cp72OcNf4hdquhHBChzSFERRDO5VoHNbTyYRgrhqXCqph6ZhlquYjq6QIWUZNBoLT2 G7bq/g3qmxAsxQ0AjDMQgfVj0j8QJcsl9PQ/A1ifrj8/4Xm9beCcC0GRPdRE8oHvaY YRrkozRtIUVgjedxd2qGUcfAEt+2Xb31QbvC9GxBM6JgupYdyMpJtn4rLrXiZmaaOZ KrkqUnAxtAZug== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v4 5/7] alpha/perf: implement ProfileMe sampling Reply-To: sashiko-reviews@lists.linux.dev To: "Matt Turner" Cc: linux-perf-users@vger.kernel.org In-Reply-To: <20261102-alpha-profileme-v4-5-61e00f5e1da8@gmail.com> References: <20261102-alpha-profileme-v4-0-61e00f5e1da8@gmail.com> <20261102-alpha-profileme-v4-5-61e00f5e1da8@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 03 Nov 2026 03:26:01 +0000 X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > The 21264 (EV67 and later) and 21364 have two performance counting modes, > and the driver only uses Aggregate mode. Its samples report the PC at > which the counter interrupt was taken, which lands a variable number of > instructions after the one that overflowed the counter. On an EV7 a > 16-instruction user loop shows up at only 4 PCs, anywhere from 15 > instructions before to 12 after the real one. >=20 > In ProfileMe mode, the instruction that overflows PCTR0 opens a window > during which PCTR1 counts, and when it closes PALcode delivers the > interrupt with that instruction's PC latched in PMPC. >=20 > Select ProfileMe with the new profileme config bit or with precise_ip, > since PMPC has no skid. PCTR_CTL[SL0] selects the mode for both > counters, so a ProfileMe event is scheduled alone and perf core > multiplexes it with other hardware events. The event type chooses the > [ ... ] > wrong path are sampled at their own PC, as ProfileMe defines them. >=20 > Suggested-by: Magnus Lindholm > Assisted-by: Claude:claude-opus-5-5 > Signed-off-by: Matt Turner Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261102-alpha-prof= ileme-v4-0-61e00f5e1da8@gmail.com?part=3D5