From nobody Tue Jan 21 23:15:48 2025 X-Original-To: dev-commits-src-all@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4Yd33T4q5Yz5lkJs; Tue, 21 Jan 2025 23:15:49 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R11" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4Yd33T2BWcz3Hvg; Tue, 21 Jan 2025 23:15:49 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1737501349; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=iLjkm56FroNDfUw7UiarxNAYl3x4kQ72ZFkmpfxPZUA=; b=TzkfVVhYIcTVuLA6ogldogL/ttHWkYvxhEmEMrFQ5U/oLK1ykdROsuNtprpwQtT6MLlarx WyGVzJzrQyZm92EcVS9mwSC7yI5nD+TpZ8URmq1wE8A1T+MJQchpLkVPdjvYWS8h92yM+8 MmmqI+pz/84mYEWlDwuxwvzIMLn8eyYzIX12PzyZD0pyQrt93Ip2TjP4iHHa+CB9de/Ciw 535o/L53mQZGGDpiDV4qms2xutOqQNV33tt2igC43y2O79xNA7lVqFLAF2fcR4gMCi19V/ KykomDqA5piNgFgjYIny/eaQ/hP/tBjN2fJHRz8RgH11HA26VuMq2sQuY8Lxng== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1737501349; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=iLjkm56FroNDfUw7UiarxNAYl3x4kQ72ZFkmpfxPZUA=; b=XtoNhwKtkk8OcyUwi55JFKO5XumkFurw5CWq27YE2FJKhB8qRlnbok45+DyU/X51jgrkQy mdpILMUYV2qZQ58YPrMKQJrYzKZb5Kriom+PKs3iwdWCNe6v007a5+mlIPHb4NFkBZYrAB VIet/M8Dst5l9VqTbF9fZeKPDdNqelvuPlXtRC8AygwEvczAaLOPnrKj9/KX4YBun/GBiR BDWurjVMTNfBcmteKWHNuCSU9OosMvHiPG6q3p3wGM9VUrObySawE6riZFPBH0PVTE9zYi 8dHGYD9AHRNS6ntZf5eNP5xQvi7zGfHHWbCSDKboSlBvkkOf4pl1nsSmORURKw== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1737501349; a=rsa-sha256; cv=none; b=VYtBqVG2mmso0tUq+x/vHeL7hbe8tfUqNs6a7BEc2kb5mn/1rixKjO9yxouOKPlKuHi+Wy +f0IDr7eoOWcDprXqnKiRkdrxsvsqSzp56dWxxdVkZVa6VaWcjYoze9XaVQ1VR3mPxWrc7 5vEnrvUVRaCnTuFxoTQ3vAMZxnXTFCu9zPiPBZDsxRLOUgO+N/4gszTDADSp4K/7hFcfUX 17My95B3m5quXfEhuHTsLzYjfjmSBPX4enD27aYrJqasgj5nvA7OIm4SKeRMYNcNc+7O5j mh97kKFE2U4QPmEMYgNnAOydGDQHVm6+J0O+wPq6L6ywUWl37hGvyZlRfBcCwg== ARC-Authentication-Results: i=1; mx1.freebsd.org; none Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4Yd33T0qmZzB6d; Tue, 21 Jan 2025 23:15:49 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.18.1/8.18.1) with ESMTP id 50LNFmWk078531; Tue, 21 Jan 2025 23:15:48 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.18.1/8.18.1/Submit) id 50LNFmKa078528; Tue, 21 Jan 2025 23:15:48 GMT (envelope-from git) Date: Tue, 21 Jan 2025 23:15:48 GMT Message-Id: <202501212315.50LNFmKa078528@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Justin Hibbits Subject: git: 58f77309c4e0 - main - Add machdep.cpu_idle_max_stop_state tunable List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-all@freebsd.org Sender: owner-dev-commits-src-all@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: jhibbits X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 58f77309c4e0d3373705582e9ca7649fe74dd267 Auto-Submitted: auto-generated The branch main has been updated by jhibbits: URL: https://cgit.FreeBSD.org/src/commit/?id=58f77309c4e0d3373705582e9ca7649fe74dd267 commit 58f77309c4e0d3373705582e9ca7649fe74dd267 Author: Timothy Pearson AuthorDate: 2025-01-20 20:03:55 +0000 Commit: Justin Hibbits CommitDate: 2025-01-21 23:14:40 +0000 Add machdep.cpu_idle_max_stop_state tunable Multiple idle and deep sleep states are supported on Power7+ platforms, with each state having a characteristic latency and effect on system real-time performance. Add a tunable to allow a maximum sleep state (maximum theoretical sleep-related latency) to be set, in order to better support specific latency-sensitive applications / real time workloads. Signed-off-by: Timothy Pearson --- sys/powerpc/powerpc/cpu.c | 40 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 39 insertions(+), 1 deletion(-) diff --git a/sys/powerpc/powerpc/cpu.c b/sys/powerpc/powerpc/cpu.c index f73ed25c8924..4b8da50cf642 100644 --- a/sys/powerpc/powerpc/cpu.c +++ b/sys/powerpc/powerpc/cpu.c @@ -95,6 +95,9 @@ static void cpu_idle_booke(sbintime_t); static void cpu_idle_e500mc(sbintime_t sbt); #endif #if defined(__powerpc64__) && defined(AIM) +static int cpu_idle_max_stop_state = 2; +SYSCTL_INT(_machdep, OID_AUTO, cpu_idle_max_stop_state, + CTLFLAG_RW, &cpu_idle_max_stop_state, 0, ""); static void cpu_idle_powerx(sbintime_t); static void cpu_idle_power9(sbintime_t); #endif @@ -815,6 +818,22 @@ cpu_idle_booke(sbintime_t sbt) static void cpu_idle_powerx(sbintime_t sbt) { + int max_stop_state = cpu_idle_max_stop_state; + + /* Limit maximum stop state to valid values */ + if (max_stop_state < 0) { + /* Don't nap at all, busy wait instead */ + cpu_idle_max_stop_state = -1; + return; + } + if (max_stop_state > 1) { + /* POWER8 and below only support the one stop state, + * i.e. 'nap' + */ + max_stop_state = 1; + cpu_idle_max_stop_state = max_stop_state; + } + /* Sleeping when running on one cpu gives no advantages - avoid it */ if (smp_started == 0) return; @@ -837,9 +856,28 @@ static void cpu_idle_power9(sbintime_t sbt) { register_t msr; + int max_stop_state = cpu_idle_max_stop_state; - msr = mfmsr(); + /* Limit maximum stop state to valid values */ + if (max_stop_state < 0) { + /* Don't stop at all, busy wait instead */ + cpu_idle_max_stop_state = -1; + return; + } + + /* Set maximum transition level to 3, for deepest lossless sleep. + * On POWER9 this is automatically downgraded to the next supported + * stop state (stop2), but other CPUs may support stop3. + */ + if (max_stop_state > 3) { + /* Stop states greater than 3 require register state save and + * restore functionality that is not yet implemented + */ + max_stop_state = 3; + cpu_idle_max_stop_state = max_stop_state; + } + msr = mfmsr(); /* Suspend external interrupts until stop instruction completes. */ mtmsr(msr & ~PSL_EE); /* Set the stop state to lowest latency, wake up to next instruction */