From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f46.google.com (mail-wr1-f46.google.com [209.85.221.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9DAC324DD17 for ; Tue, 27 May 2025 09:59:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.46 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748339997; cv=none; b=ZZaagE7FpcnD6aw4pE3YsISLv+Zt55g/jRhyaWYkM3e9pBkRF4Rf8TOhOyps0F795dEr/pxyrRI93WRYPszKAsbOMvjZkA6KZ1I9O9VwN3ike8cZEfPELiINV6uIptHPYwG4MX1bNu3zAMBSM8qyxwc512vSGGAUNJknie/F210= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748339997; c=relaxed/simple; bh=MzOvGX8O+4utQ4eU3Iajmah5bipRwCmAxAIkr/YrneE=; h=MIME-Version:References:In-Reply-To:From:Date:Message-ID:Subject: To:Cc:Content-Type; b=gHim2iW97+PdgnP8c6APTxs6/iWfjZKqsOX4V25cNAy1ja4K8iAFCM5PmMT6CQLciYvnSCfLeYTDe9uXTReMBdKNVZS8TtRDUbOiUnHKjYlICSGUTtYHHy31Mo7W//wqrnbdyVqPfVgp5TbMzMyqNwcJpjyJ0d47wpkA1rwboaE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=rivosinc.com; spf=pass smtp.mailfrom=rivosinc.com; dkim=pass (2048-bit key) header.d=rivosinc-com.20230601.gappssmtp.com header.i=@rivosinc-com.20230601.gappssmtp.com header.b=VnQLdZeL; arc=none smtp.client-ip=209.85.221.46 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=rivosinc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rivosinc.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=rivosinc-com.20230601.gappssmtp.com header.i=@rivosinc-com.20230601.gappssmtp.com header.b="VnQLdZeL" Received: by mail-wr1-f46.google.com with SMTP id ffacd0b85a97d-3a37a243388so3222959f8f.1 for ; Tue, 27 May 2025 02:59:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20230601.gappssmtp.com; s=20230601; t=1748339994; x=1748944794; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=o4DLlx+hKQhw+ENgyFAqY2PL5hW4DHMG/cxZu2R2Xik=; b=VnQLdZeL7eOji61GOi7HPGKca7NmU8WKZcqkehppqcA4IRKmDSOKCJrlYt4HlmKPpa eU6KKNINEfg8PZk3Pwek9poAcCqF/Tv5Y4by5Yc6Apt0pdGRpVlB/T+CcDEV60/pGIHu MD5er/23EVDP2Bsyzxdj7696KH8cZjSXkY23qXG7Q7/ekSiI8NR5tZb85VCPQC04iWMS PrsdakJ7e0TJbq451Nple24CBk5DGAZpZW0pV0BWfN2SZi6wBNb8MfOlIXHXaaSjM+Ky Dd4wTBqQQ79dVBtPHsIj2JaAzYTbC94IWzgcAp1PZDmkyI4cbQEUh9+2m8p6VnXPfS2C bb3g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1748339994; x=1748944794; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=o4DLlx+hKQhw+ENgyFAqY2PL5hW4DHMG/cxZu2R2Xik=; b=dSXDNDBdbCJHlwoIBJr2IZa9hg/kQsVV5ewNJVJgoHdd+oC98/8L9+ivkrR+F1i6Dt YEEk5vKyVG9ycWjbalHPtnlHcZQkn0Z3XOmpd1PnuqJPMF6OVAMev4nkJIk069k9vtKd mcNGm6pM3/Bl2L1MC4g6Z7X37WtO8DXOJVBBo5cGETL45w3cT4I70bkrcRc+z5wtbVhE CbCXUb9vss/6YKmXxSgIjnghvmWRaanx9kk7ky+lfXUvcH7cgkcQtIDdnmsilpkf9aAp 6vRuMhfqfECnnTGRXtnEEGgcEfzYvzfRVADOjBxPNHvvwNBLEfaSJvdZJjTUcPFmjPTX KVOQ== X-Gm-Message-State: AOJu0YyNw5sKvF/gcy4Px6eLcaV5X3f1gh1iRcExoHNBVV+/tyDBJ9TV /dWKpvBDnT8dAbrbDHfRg12XYEMnPV2KS6MIXmp2k1J4ZzppkyU6lQuasNdim4pXD/ulJAhZhco gxxBT9mg9GXVfbrP+jBjFB4lP1N8K7PlTd0wmFcs21w== X-Gm-Gg: ASbGnctiD/U/fBm3JTk2vLnad/yxq3PYsTHjlHzI+Fx9Rh61TsXe7wsQnyVV8X2dySq N3EHt3C4uiHsX7A/H2IC/SwFiKHBm8cBG+can5X7lkyzrU19FyY79idxCmETa+RqBZdiivZxLJ0 BPpfGS6EEH7HkDStyr4+xNCHmDqE5NVvg= X-Google-Smtp-Source: AGHT+IEW4jiGzBYUUJeQ+hZ9q3VAC3c3XCEXdCJkYQj3sC6I500v3SraZXfwDAQYqmh+I1E3eL9qo1sRnEJZg8HQc9I= X-Received: by 2002:a05:6000:240d:b0:3a4:d6ed:8e07 with SMTP id ffacd0b85a97d-3a4d6eda68cmr5556606f8f.32.1748339993821; Tue, 27 May 2025 02:59:53 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20250523-b4-ctr_upstream_v3-v3-0-ad355304ba1c@rivosinc.com> <20250523-b4-ctr_upstream_v3-v3-1-ad355304ba1c@rivosinc.com> In-Reply-To: <20250523-b4-ctr_upstream_v3-v3-1-ad355304ba1c@rivosinc.com> From: Rajnesh Kanwal Date: Tue, 27 May 2025 10:59:41 +0100 X-Gm-Features: AX0GCFvLUhtMwBzFmk1b4gn3Tur4pK0okxD3qyqun7XWisCr-irbPglToM7Uhec Message-ID: Subject: Re: [PATCH v3 1/7] perf: Increase the maximum number of branches remove_loops() can process. To: ak@linux.intel.com, Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Atish Kumar Patra , Anup Patel , Will Deacon , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Beeman Strong Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, linux-arm-kernel@lists.infradead.org, Conor Dooley , devicetree@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Adding Andi Kleen as this was originally written by him. -Rajnesh On Fri, May 23, 2025 at 12:26=E2=80=AFAM Rajnesh Kanwal wrote: > > RISCV CTR extension supports a maximum depth of 256 last branch records. > Currently remove_loops() can only process 127 entries at max. This leads > to samples with more than 127 entries being skipped. This change simply > updates the remove_loops() logic to be able to process 256 entries. > > Signed-off-by: Rajnesh Kanwal > --- > tools/perf/util/machine.c | 21 ++++++++++++++------- > 1 file changed, 14 insertions(+), 7 deletions(-) > > diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c > index 2d51badfbf2e2d1588fa4fdd42ef6c8fea35bf0e..5414528b9d336790decfb42a4= f6a4da6c6b68b07 100644 > --- a/tools/perf/util/machine.c > +++ b/tools/perf/util/machine.c > @@ -2176,25 +2176,32 @@ static void save_iterations(struct iterations *it= er, > iter->cycles +=3D be[i].flags.cycles; > } > > -#define CHASHSZ 127 > -#define CHASHBITS 7 > -#define NO_ENTRY 0xff > +#define CHASHBITS 8 > +#define NO_ENTRY 0xffU > > -#define PERF_MAX_BRANCH_DEPTH 127 > +#define PERF_MAX_BRANCH_DEPTH 256 > > /* Remove loops. */ > +/* Note: Last entry (i=3D=3Dff) will never be checked against NO_ENTRY > + * so it's safe to have an unsigned char array to process 256 entries > + * without causing clash between last entry and NO_ENTRY value. > + */ > static int remove_loops(struct branch_entry *l, int nr, > struct iterations *iter) > { > int i, j, off; > - unsigned char chash[CHASHSZ]; > + unsigned char chash[PERF_MAX_BRANCH_DEPTH]; > > memset(chash, NO_ENTRY, sizeof(chash)); > > - BUG_ON(PERF_MAX_BRANCH_DEPTH > 255); > + BUG_ON(PERF_MAX_BRANCH_DEPTH > 256); > > for (i =3D 0; i < nr; i++) { > - int h =3D hash_64(l[i].from, CHASHBITS) % CHASHSZ; > + /* Remainder division by PERF_MAX_BRANCH_DEPTH is not > + * needed as hash_64 will anyway limit the hash > + * to CHASHBITS > + */ > + int h =3D hash_64(l[i].from, CHASHBITS); > > /* no collision handling for now */ > if (chash[h] =3D=3D NO_ENTRY) { > > -- > 2.43.0 >