From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752903AbdLBQQB (ORCPT ); Sat, 2 Dec 2017 11:16:01 -0500 Received: from omzsmtpe01.verizonbusiness.com ([199.249.25.210]:7438 "EHLO omzsmtpe01.verizonbusiness.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752575AbdLBPww (ORCPT ); Sat, 2 Dec 2017 10:52:52 -0500 From: alexander.levin@verizon.com Cc: Vaidyanathan Srinivasan , Michael Ellerman , alexander.levin@verizon.com X-Host: endeavour.tdc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH AUTOSEL for 4.14 55/64] powerpc/powernv/idle: Round up latency and residency values Thread-Topic: [PATCH AUTOSEL for 4.14 55/64] powerpc/powernv/idle: Round up latency and residency values Thread-Index: AQHTa4VxgybCurJdS0u8lCe5UAmgqA== Date: Sat, 2 Dec 2017 15:51:39 +0000 Message-ID: <20171202155101.7573-55-alexander.levin@verizon.com> References: <20171202155101.7573-1-alexander.levin@verizon.com> In-Reply-To: <20171202155101.7573-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id vB2GGCLr027793 From: Vaidyanathan Srinivasan [ Upstream commit 8d4e10e9ed9450e18fbbf6a8872be0eac9fd4999 ] On PowerNV platforms, firmware provides exit latency and target residency for each of the idle states in nano seconds. Cpuidle framework expects the values in micro seconds. Round up to nearest micro seconds to avoid errors in cases where the values are defined as fractional micro seconds. Default idle state of 'snooze' has exit latency of zero. If other states have fractional micro second exit latency, they would get rounded down to zero micro second and make cpuidle framework choose deeper idle state when snooze loop is the right choice. Reported-by: Anton Blanchard Signed-off-by: Vaidyanathan Srinivasan Reviewed-by: Gautham R. Shenoy Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin --- drivers/cpuidle/cpuidle-powernv.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c index ed6531f075c6..e06605b21841 100644 --- a/drivers/cpuidle/cpuidle-powernv.c +++ b/drivers/cpuidle/cpuidle-powernv.c @@ -384,9 +384,9 @@ static int powernv_add_idle_states(void) * Firmware passes residency and latency values in ns. * cpuidle expects it in us. */ - exit_latency = latency_ns[i] / 1000; + exit_latency = DIV_ROUND_UP(latency_ns[i], 1000); if (!rc) - target_residency = residency_ns[i] / 1000; + target_residency = DIV_ROUND_UP(residency_ns[i], 1000); else target_residency = 0; -- 2.11.0