From patchwork Thu Aug 15 01:46:27 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Liao, Chang" X-Patchwork-Id: 13764359 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EB90917C9; Thu, 15 Aug 2024 01:55:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.255 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723686960; cv=none; b=rdpHKSP8HIqdRlH+AwqcPVu9ozXr4aIJX8D9JQ9NVfxQ4VT6JIRTwL8TKhITERAFYhCz6nKNvxhUzfc4DLEybtdQWUBiDde1ipYNJ2hZFDTqYK+N0tqiomh0ICJLSKpA2FwqsRTSGCs3SowmcuUVF+ieOl9Akv8q1BBUhNOYA64= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723686960; c=relaxed/simple; bh=jS9I6vz/mLqWFHm0al0X2/o7/JXJYiIVeFzeJPA0xrs=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=bMO3fDOW++PqAbmDo3hIWj9jbHthtsaNHZ1/PYz4sILxa8EkKAFHPnSbcNKIXy5KdMC/MHVlcELSNx4EHqM9KRFQVsFWggLuQYbGVFTdlwP97/7SUzs1UNfEG3P9CAKq0hTpwWErX7Dtw/R1SLI4kO2yxIfAVEVW0xkIdDfpnqw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.255 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.48]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4Wkp9K1NPHz1T77H; Thu, 15 Aug 2024 09:55:17 +0800 (CST) Received: from kwepemd200013.china.huawei.com (unknown [7.221.188.133]) by mail.maildlp.com (Postfix) with ESMTPS id BA3DB18006C; Thu, 15 Aug 2024 09:55:47 +0800 (CST) Received: from huawei.com (10.67.174.28) by kwepemd200013.china.huawei.com (7.221.188.133) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.34; Thu, 15 Aug 2024 09:55:46 +0800 From: Liao Chang To: , , , , , , , , , , , CC: , , , Subject: [PATCH v3 0/2] uprobes: Improve scalability by reducing the contention on siglock Date: Thu, 15 Aug 2024 01:46:27 +0000 Message-ID: <20240815014629.2685155-1-liaochang1@huawei.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To kwepemd200013.china.huawei.com (7.221.188.133) The profiling result of BPF selftest on ARM64 platform reveals the significant contention on the current->sighand->siglock is the scalability bottleneck. The reason is also very straightforward that all producer threads of benchmark have to contend the spinlock mentioned to resume the TIF_SIGPENDING bit in thread_info that might be removed in uprobe_deny_signal(). The contention on current->sighand->siglock is unnecessary, this series remove them thoroughly. I've use the script developed by Andrii in [1] to run benchmark. The CPU used was Kunpeng916 (Hi1616), 4 NUMA nodes, 64 cores@2.4GHz running the kernel on next tree + the optimization in [2] for get_xol_insn_slot(). before-opt ---------- uprobe-nop ( 1 cpus): 0.907 ± 0.003M/s ( 0.907M/s/cpu) uprobe-nop ( 2 cpus): 1.676 ± 0.008M/s ( 0.838M/s/cpu) uprobe-nop ( 4 cpus): 3.210 ± 0.003M/s ( 0.802M/s/cpu) uprobe-nop ( 8 cpus): 4.457 ± 0.003M/s ( 0.557M/s/cpu) uprobe-nop (16 cpus): 3.724 ± 0.011M/s ( 0.233M/s/cpu) uprobe-nop (32 cpus): 2.761 ± 0.003M/s ( 0.086M/s/cpu) uprobe-nop (64 cpus): 1.293 ± 0.015M/s ( 0.020M/s/cpu) uprobe-push ( 1 cpus): 0.883 ± 0.001M/s ( 0.883M/s/cpu) uprobe-push ( 2 cpus): 1.642 ± 0.005M/s ( 0.821M/s/cpu) uprobe-push ( 4 cpus): 3.086 ± 0.002M/s ( 0.771M/s/cpu) uprobe-push ( 8 cpus): 3.390 ± 0.003M/s ( 0.424M/s/cpu) uprobe-push (16 cpus): 2.652 ± 0.005M/s ( 0.166M/s/cpu) uprobe-push (32 cpus): 2.713 ± 0.005M/s ( 0.085M/s/cpu) uprobe-push (64 cpus): 1.313 ± 0.009M/s ( 0.021M/s/cpu) uprobe-ret ( 1 cpus): 1.774 ± 0.000M/s ( 1.774M/s/cpu) uprobe-ret ( 2 cpus): 3.350 ± 0.001M/s ( 1.675M/s/cpu) uprobe-ret ( 4 cpus): 6.604 ± 0.000M/s ( 1.651M/s/cpu) uprobe-ret ( 8 cpus): 6.706 ± 0.005M/s ( 0.838M/s/cpu) uprobe-ret (16 cpus): 5.231 ± 0.001M/s ( 0.327M/s/cpu) uprobe-ret (32 cpus): 5.743 ± 0.003M/s ( 0.179M/s/cpu) uprobe-ret (64 cpus): 4.726 ± 0.016M/s ( 0.074M/s/cpu) after-opt --------- uprobe-nop ( 1 cpus): 0.985 ± 0.002M/s ( 0.985M/s/cpu) uprobe-nop ( 2 cpus): 1.773 ± 0.005M/s ( 0.887M/s/cpu) uprobe-nop ( 4 cpus): 3.304 ± 0.001M/s ( 0.826M/s/cpu) uprobe-nop ( 8 cpus): 5.328 ± 0.002M/s ( 0.666M/s/cpu) uprobe-nop (16 cpus): 6.475 ± 0.002M/s ( 0.405M/s/cpu) uprobe-nop (32 cpus): 4.831 ± 0.082M/s ( 0.151M/s/cpu) uprobe-nop (64 cpus): 2.564 ± 0.053M/s ( 0.040M/s/cpu) uprobe-push ( 1 cpus): 0.964 ± 0.001M/s ( 0.964M/s/cpu) uprobe-push ( 2 cpus): 1.766 ± 0.002M/s ( 0.883M/s/cpu) uprobe-push ( 4 cpus): 3.290 ± 0.009M/s ( 0.823M/s/cpu) uprobe-push ( 8 cpus): 4.670 ± 0.002M/s ( 0.584M/s/cpu) uprobe-push (16 cpus): 5.197 ± 0.004M/s ( 0.325M/s/cpu) uprobe-push (32 cpus): 5.068 ± 0.161M/s ( 0.158M/s/cpu) uprobe-push (64 cpus): 2.605 ± 0.026M/s ( 0.041M/s/cpu) uprobe-ret ( 1 cpus): 1.833 ± 0.001M/s ( 1.833M/s/cpu) uprobe-ret ( 2 cpus): 3.384 ± 0.003M/s ( 1.692M/s/cpu) uprobe-ret ( 4 cpus): 6.677 ± 0.004M/s ( 1.669M/s/cpu) uprobe-ret ( 8 cpus): 6.854 ± 0.005M/s ( 0.857M/s/cpu) uprobe-ret (16 cpus): 6.508 ± 0.006M/s ( 0.407M/s/cpu) uprobe-ret (32 cpus): 5.793 ± 0.009M/s ( 0.181M/s/cpu) uprobe-ret (64 cpus): 4.743 ± 0.016M/s ( 0.074M/s/cpu) Above benchmark results demonstrates a obivious improvement in the scalability of trig-uprobe-nop and trig-uprobe-push, the peak throughput of which are from 4.5M/s to 6.4M/s and 3.3M/s to 5.1M/s individually. v3->v2: Renaming the flag in [2/2], s/deny_signal/signal_denied/g. v2->v1: Oleg pointed out the _DENY_SIGNAL will be replaced by _ACK upon the completion of singlestep which leads to handle_singlestep() has no chance to restore the removed TIF_SIGPENDING [3] and some case in question. So this revision proposes to use a flag in uprobe_task to track the denied TIF_SIGPENDING instead of new UPROBE_SSTEP state. [1] https://lore.kernel.org/all/20240731214256.3588718-1-andrii@kernel.org [2] https://lore.kernel.org/all/20240727094405.1362496-1-liaochang1@huawei.com [3] https://lore.kernel.org/all/20240801082407.1618451-1-liaochang1@huawei.com Liao Chang (2): uprobes: Remove redundant spinlock in uprobe_deny_signal() uprobes: Remove the spinlock within handle_singlestep() include/linux/uprobes.h | 1 + kernel/events/uprobes.c | 10 +++++----- 2 files changed, 6 insertions(+), 5 deletions(-)