From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f74.google.com (mail-wr1-f74.google.com [209.85.221.74]) (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 5429641DE18 for ; Wed, 15 Jul 2026 09:17:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784107087; cv=none; b=U+J+3QbKde6RtHZxDUhwjrBb5BCHy6NcfWlnM79KvRXzOICowMNk7QjLC0Pi0AD81GvHkzTldyIn0vOPrL+plvWPK/cB0sIDX4VJ5Hjtha3Q+xzt+eeNQQ98boxPvRrfBNuHQuhNyMiQjvjzsi94Nl/hFKR8uMJsYA1g8UoXS04= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784107087; c=relaxed/simple; bh=2ib1YCF+qLA0g0zM7abYfnmu0Qgxm8C6pSzSfDaq6RM=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=I6Y8jLHwMsXRuRcWtanJGS+Wyd4yeZzt753HICt/dUSVTk/4mN0XQ2aqEk4gbcSEzlLjvUrWWsF2bEpn06xzk2Fhlc+P/dt7ANgha/587HnM4cFLtaozVqP8L5bFjrsJgzQH2o2kyE90Em9suWxdJb1Bo9Vc9zOo2Sm5khiAMAM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--aliceryhl.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=KWQ3DV9h; arc=none smtp.client-ip=209.85.221.74 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--aliceryhl.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="KWQ3DV9h" Received: by mail-wr1-f74.google.com with SMTP id ffacd0b85a97d-473e18559b2so1115414f8f.0 for ; Wed, 15 Jul 2026 02:17:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1784107070; x=1784711870; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=HnI7wLu70CvRUXyaBngCe2u8116FcC45Wmg8KkFg5z0=; b=KWQ3DV9hhq2jEgSHsDoQC/W5u03vfvSJejO2ga8q4TT9uQNlnn4X3XOCpE2CVYQklV Hor9brusxBPg+52Hb2QOPNSks5j5CJJtplNXP91XmzqGsuR4Zco+d236VsPINomBgeCt N/s2+kyQLvVQ4/r4xQmMQq+8JOvmFZVrgVH/YH5X43TmkE+g39z5rcDLs1tQ8u/suioT DWSoCZWshBqLGVJhzLGFFCEKkxhx1It26y6Ha6vZv9na+kztKJ8k+lncwOXinxTWkS8l XaR591A2SaWZe0SZ9Od3qW2cckjjjWD+WetTtsXlYV+9Z1c6E2Jd6/2vUzYBEzwNDYAl 0WIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784107070; x=1784711870; h=content-type: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:content-type; bh=HnI7wLu70CvRUXyaBngCe2u8116FcC45Wmg8KkFg5z0=; b=LAQ53ux5eo+VZH8vxT9Dts8FcwO+Zf4Ch16mI3Lm4wj+CW877ErW2KoFDEr/SefeB0 3dFHlbWCE6EJmpbkH44VUVza1c027tEqPixb8Cy4h0YyHBqgYM7wptslSD5PYI6i3KOk daPof3bfB54DN2dlFboSHSJjheKSRqAblCm6dzQ8UuiBa/vxqIkKSzzHWUttNEkFL5sp yfLzHDJk0zzo9j1E27oaDWfpAqlm5LmBc5hD314TDPyM+139E2lp3z+6EI/a/UZJ8rOt 4PzaQVLVHRNgLjKMxOi/lNJUF0G1RKNQRU1C+NnOjwQLp4r5hlaCxUUlC3YhNhk3DHnQ sLFA== X-Forwarded-Encrypted: i=1; AHgh+RqPsshduEUav3uPoOsJopUvTAlOlE4lWd8Jj4RfQxp+KGUPmCcbohG4BY/Af/XMuTOT4rol4yVfCvmKhGw=@vger.kernel.org X-Gm-Message-State: AOJu0YypkcrIfNJLaUWMICbMjh8OXSaigrSeXgPK0oRjflrpPVlsM8v+ La+hqJn56570eBPCBo+l24gG/lZLDIYpNUquAduoXolJeMbmvFElhY+jCIsBhyHtnyadNyk86DP 6MRgMIevNm/vNrIyoIA== X-Received: from wmbz15.prod.google.com ([2002:a05:600c:c08f:b0:493:f434:c988]) (user=aliceryhl job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:310f:b0:493:ee3a:f05b with SMTP id 5b1f17b1804b1-493f87d7fcdmr168622875e9.7.1784107070173; Wed, 15 Jul 2026 02:17:50 -0700 (PDT) Date: Wed, 15 Jul 2026 09:17:48 +0000 In-Reply-To: <20260714183553.39773-1-trieu2.huynh@lge.corp-partner.google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260714183553.39773-1-trieu2.huynh@lge.corp-partner.google.com> Message-ID: Subject: Re: [PATCH 0/2] drivers: android: binder: Introduce Cluster Aware Thread Selection From: Alice Ryhl To: "trieu2.huynh" Cc: gregkh@linuxfoundation.org, arve@android.com, tkjos@android.com, brauner@kernel.org, cmllamas@google.com, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" On Wed, Jul 15, 2026 at 03:35:50AM +0900, trieu2.huynh wrote: > Motivation > ---------- > > On asymmetric multi-cluster ARM64 SoCs, the default binder thread > selection is topology-blind. Cross-cluster thread wakeups incur severe > cache-coherency overhead. > > Measured performance test [1], especially with schd-dbg tiered threads [2] > on baseline (10K iter, 16B payload): > > Class Tier Avg Latency Count / % of txns > ----- ---- ----------- ----------------- > SCHED_FIFO Same-core 0.089 ms 9,963 / 99.6% > (max prio) Same-cluster 0.120 ms 13 / 0.1% > Cross-cluster 0.140 ms 24 / 0.2% > ----------------------------------------------------- > Normal Same-core 0.130 ms 4,623 / 46.2% > (Other) Same-cluster 0.140 ms 3,290 / 32.9% > Cross-cluster 0.190 ms 2,087 / 20.9% > > Key Observations: > (*) For SCHED_FIFO tasks, the scheduler aggressively locks the affinity, > keeping 99.6% of txns on the same core, establishing the hardware's > ideal latency ceiling (~0.089 ms). > (*) For normal tasks, selection is highly fragmented (only 46.2% on > same-core). Cross-cluster transactions are ~46% slower (0.19 vs > 0.13 ms) due to interconnect overhead and cache invalidation. > (*) CTABS aims to close this gap for normal threads by enforcing affinity. I've been told that GKI has patched wake_up_sync() to make it place the recipient on the same CPU if nothing else is scheduled to run there. * http://r.android.com/1362918 * http://r.android.com/1145589 Are these patches included in the tree from which you took this benchmark? Alice