From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dl1-f73.google.com (mail-dl1-f73.google.com [74.125.82.73]) (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 81D232C1594 for ; Tue, 17 Mar 2026 03:06:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773716774; cv=none; b=m3Z9T1DD93aPXPGYPPvyHip1c0mwPRs9hKu1OZmz/h55PVf5KIrnRoJy3B4Df3z3GebfLiz51j9EF4CO6cZ9XLPxp+7YoDhilWMxvO3A9o4Smshohn2GvtVWf1m4fu7j6lZiaPzmKHtJaqV0pR93E6uB8l+otPgq31UJu3rwb3g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773716774; c=relaxed/simple; bh=wVIk574MaJ1ryn6M1d5QWZAOYLPanqIo/c++6wESi+o=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=bgVGTt/r2lq0hzDTFCPEzj5/vuUohqmBX5r+P1XgziqZLodrpe16EgMypvLcvNL/3t/NfbPWqrb7ZmZhndiIny8Z6y442NovIYMT9wwbluUkEgsT/vjsIqLxzMJ+0F7VVTaYGhWRsO7IZzaoE1cmxvqmHWsUp/3AWfoiBToSuN4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=kc5Zsrc7; arc=none smtp.client-ip=74.125.82.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="kc5Zsrc7" Received: by mail-dl1-f73.google.com with SMTP id a92af1059eb24-128d0a51897so105890383c88.0 for ; Mon, 16 Mar 2026 20:06:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1773716773; x=1774321573; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=BC7DFlkd9xaG2royXDyXDCwOCftcIJRM1qoiGuRC8ho=; b=kc5Zsrc75XtQXWMlr9QFNaqSkuB0Pj8HMKsqmsEzWKZbEvzDTHgUz6fbuDR8tSHJDW BJgJ0d5HDruUjQ2v6cJ5RgM0PiQxJmqPNQk5XIq+PskB4v6pyhS6FS6z3sMPdPz5KxUZ QqLas6rMF+IJVjy38ioJGeSXyPiJbkv3goNLqDaHGkv8Mk0MUFTMEFNS3FDJu+xEJL+5 Pu4D9ATtznrdbkZjzWfaKWXvdv8d0NuJtTx94SMQ+V17LFHJkGehlrqsGzZ63/tUk8vi DG7Be8QMjqqbCpnQAYvimeCnxbOevh4zpk6SYdcBYxucHaU9120kZ/TB0FSVyJgGWwS1 dggw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1773716773; x=1774321573; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=BC7DFlkd9xaG2royXDyXDCwOCftcIJRM1qoiGuRC8ho=; b=fUeqvqQ0KD/3z48AYwQt0YwKRFCBBVYOvM56H/iop3NojYDU+bp0MWTpNJb2yAqJUA u7LHnRpuhLyP3u73dRbbt34GuZt8jzR9zilmSj7qk4gCZn8iNh2SEvZQSmQsY9peU5vz LE3mqHuDzXhY28GXGP9xkeOaJC7OtFlaAofnIlN2ma+FQ++6nxJJvFxxuCZGLy/ztoAf gsTOgbLp8hDasT/Gzuw9gBDrHW6t+rhUUT9Xmo1OfmA/WllqPDX4y0zPkv4dNNEdMJbN iaxnuWln8EL1aH1OSyRFD6LbwiGjxS0S5BV9DR72+Gu8GWrX3MX/9vTbkpmxU6mlWQu2 ZRYw== X-Forwarded-Encrypted: i=1; AJvYcCWX/zFWpU4J8O5uv0ZsAIblpR26mpEYt0eJYL+LmsXFxXbBcUCDjN2lDlrnP7jzev21bPZeAgNO+NkfUvKSb+pb@vger.kernel.org X-Gm-Message-State: AOJu0YzbJixOAkBY2VCr/ouHnCnu6Bzkzje2JcKx2st2QGrFRDLCU2qh 8PPalJugRwUsEQdpl4i3A26jaaR1yZfQTAXvoHbcu5y2uJn4HdtIm5GKiaLqoPStqfiUJrRzH8A 3UShL/UacrA== X-Received: from dlae14.prod.google.com ([2002:a05:701b:230e:b0:128:d97e:9ee4]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7022:2393:b0:11b:2de8:6271 with SMTP id a92af1059eb24-128f3e350bcmr7954454c88.39.1773716772453; Mon, 16 Mar 2026 20:06:12 -0700 (PDT) Date: Mon, 16 Mar 2026 20:05:57 -0700 In-Reply-To: <20260317030601.567422-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260317030601.567422-1-irogers@google.com> X-Mailer: git-send-email 2.53.0.851.ga537e3e6e9-goog Message-ID: <20260317030601.567422-2-irogers@google.com> Subject: [PATCH v4 1/5] perf evsel: Improve falling back from cycles From: Ian Rogers To: tmricht@linux.ibm.com Cc: irogers@google.com, acme@kernel.org, agordeev@linux.ibm.com, gor@linux.ibm.com, hca@linux.ibm.com, japo@linux.ibm.com, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-s390@vger.kernel.org, namhyung@kernel.org, sumanthk@linux.ibm.com Content-Type: text/plain; charset="UTF-8" Switch to using evsel__match rather than comparing perf_event_attr values, this is robust on hybrid architectures. Ensure evsel->pmu matches the evsel->core.attr. Remove exclude bits that get set in other fallback attempts when switching the event. Log the event name with modifiers when switching the event on fallback. Signed-off-by: Ian Rogers --- tools/perf/util/evsel.c | 45 ++++++++++++++++++++++++++++------------- tools/perf/util/evsel.h | 2 ++ 2 files changed, 33 insertions(+), 14 deletions(-) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index f59228c1a39e..bd14d9bbc91f 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -3785,25 +3785,42 @@ bool evsel__fallback(struct evsel *evsel, struct target *target, int err, { int paranoid; - if ((err == ENOENT || err == ENXIO || err == ENODEV) && - evsel->core.attr.type == PERF_TYPE_HARDWARE && - evsel->core.attr.config == PERF_COUNT_HW_CPU_CYCLES) { + if ((err == ENODEV || err == ENOENT || err == ENXIO) && + evsel__match(evsel, HARDWARE, HW_CPU_CYCLES)) { /* - * If it's cycles then fall back to hrtimer based cpu-clock sw - * counter, which is always available even if no PMU support. - * - * PPC returns ENXIO until 2.6.37 (behavior changed with commit - * b0a873e). + * If it's the legacy hardware cycles event fails then fall back + * to hrtimer based cpu-clock sw counter, which is always + * available even if no PMU support. PPC returned ENXIO rather + * than ENODEV or ENOENT until 2.6.37. */ - evsel->core.attr.type = PERF_TYPE_SOFTWARE; + evsel->pmu = perf_pmus__find_by_type(PERF_TYPE_SOFTWARE); + assert(evsel->pmu); /* software is a "well-known" and can't fail PMU type. */ + + /* Configure the event. */ + evsel->core.attr.type = PERF_TYPE_SOFTWARE; evsel->core.attr.config = target__has_cpu(target) ? PERF_COUNT_SW_CPU_CLOCK : PERF_COUNT_SW_TASK_CLOCK; - scnprintf(msg, msgsize, - "The cycles event is not supported, trying to fall back to %s", - target__has_cpu(target) ? "cpu-clock" : "task-clock"); + evsel->core.is_pmu_core = false; + + /* Remove excludes for new event. */ + if (evsel->fallenback_eacces) { + evsel->core.attr.exclude_kernel = 0; + evsel->core.attr.exclude_hv = 0; + evsel->fallenback_eacces = false; + } + if (evsel->fallenback_eopnotsupp) { + evsel->core.attr.exclude_guest = 0; + evsel->fallenback_eopnotsupp = false; + } + /* Name is recomputed by evsel__name. */ zfree(&evsel->name); + + /* Log message. */ + scnprintf(msg, msgsize, + "The cycles event is not supported, trying to fall back to %s", + evsel__name(evsel)); return true; } else if (err == EACCES && !evsel->core.attr.exclude_kernel && (paranoid = perf_event_paranoid()) > 1) { @@ -3830,7 +3847,7 @@ bool evsel__fallback(struct evsel *evsel, struct target *target, int err, " samples", paranoid); evsel->core.attr.exclude_kernel = 1; evsel->core.attr.exclude_hv = 1; - + evsel->fallenback_eacces = true; return true; } else if (err == EOPNOTSUPP && !evsel->core.attr.exclude_guest && !evsel->exclude_GH) { @@ -3851,7 +3868,7 @@ bool evsel__fallback(struct evsel *evsel, struct target *target, int err, /* Apple M1 requires exclude_guest */ scnprintf(msg, msgsize, "Trying to fall back to excluding guest samples"); evsel->core.attr.exclude_guest = 1; - + evsel->fallenback_eopnotsupp = true; return true; } no_fallback: diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h index a3d754c029a0..97f57fab28ce 100644 --- a/tools/perf/util/evsel.h +++ b/tools/perf/util/evsel.h @@ -124,6 +124,8 @@ struct evsel { bool default_metricgroup; /* A member of the Default metricgroup */ bool default_show_events; /* If a default group member, show the event */ bool needs_uniquify; + bool fallenback_eacces; + bool fallenback_eopnotsupp; struct hashmap *per_pkg_mask; int err; int script_output_type; -- 2.53.0.851.ga537e3e6e9-goog