From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D9E11CF31B0 for ; Wed, 19 Nov 2025 12:26:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=fBhuu4FivJVENb+VBUSurHSnq06dWG/6fz4I3f49vfM=; b=DPvXPUCah7iDormMJo9hc1xQRe jwqnsLZNtQwh85s1nslkJ5sAUU1qo1T9CCiHTnI193VGfx4EU8KLfseY0SV8ZaLxcsXsKiqK2Qc5/ RpW8Ic/2Il01fiUhQgphLXzDY+vFbGfOTtWWdwsLXqVGsT7TIsiClOA5+mm6BInToOWDF0KzusTAf OThM4BI8rKTAjGAARP/bT7FGSCw0cCDmIDm0N6DPOCbE1zFZ+hKUC19NNqHAMZMFtIh0GOvE/l7R2 /KjF8YFxlab7l4uyjbFOcdBF42FyCx6zAVvFVQSNFB+EQ2XK24WHZxcp3YEASZDoDqvQCkXYebaGF ytG5p/SQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vLhGJ-000000038rV-30Fc; Wed, 19 Nov 2025 12:26:15 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vLhGH-000000038nh-0aHj for linux-arm-kernel@bombadil.infradead.org; Wed, 19 Nov 2025 12:26:13 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=fBhuu4FivJVENb+VBUSurHSnq06dWG/6fz4I3f49vfM=; b=pGw/d5s6j4f6WsM7FKqTLWlRSs H9YmqjuycmR+GsYiT/TlmwXsKslRjaL5vQWzWNjqR5egqRjhIwvWf3KYEhs4cdQqQKV60/2mfvmpt 63jnbkmj22U698a5fZ78u86etNj4K+1NYxJmKYCD42b87JCuFQ3SX7rPERiVRYFVlpw98n1DLj8tJ iSdHJV9e9znUv3wSmhPtNc3hGlqaPaDoRYfmTI0HIEzKIviUiMaKdN/blnHAPxqS0knemwYalaUUN +M7AlQZr1YKiBoZ7oozmmj8+d2vp66GJAbxDVFGFH8yzXH75+9cfM+fHgrwtXgN38QgYf40A+qSD0 TACV33hA==; Received: from foss.arm.com ([217.140.110.172]) by casper.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vLhG8-0000000H3eW-3GOZ for linux-arm-kernel@lists.infradead.org; Wed, 19 Nov 2025 12:26:12 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0799E1BCA; Wed, 19 Nov 2025 04:25:55 -0800 (PST) Received: from e134344.cambridge.arm.com (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 66EEA3F740; Wed, 19 Nov 2025 04:25:57 -0800 (PST) From: Ben Horgan To: james.morse@arm.com Cc: amitsinght@marvell.com, baisheng.gao@unisoc.com, baolin.wang@linux.alibaba.com, bobo.shaobowang@huawei.com, carl@os.amperecomputing.com, catalin.marinas@arm.com, dakr@kernel.org, dave.martin@arm.com, david@redhat.com, dfustini@baylibre.com, fenghuay@nvidia.com, gregkh@linuxfoundation.org, gshan@redhat.com, guohanjun@huawei.com, jeremy.linton@arm.com, jonathan.cameron@huawei.com, kobak@nvidia.com, lcherian@marvell.com, lenb@kernel.org, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, lpieralisi@kernel.org, peternewman@google.com, quic_jiles@quicinc.com, rafael@kernel.org, robh@kernel.org, rohit.mathew@arm.com, scott@os.amperecomputing.com, sdonthineni@nvidia.com, sudeep.holla@arm.com, tan.shaopeng@fujitsu.com, will@kernel.org, xhao@linux.alibaba.com, reinette.chatre@intel.com, Ben Horgan , Zeng Heng , Shaopeng Tan Subject: [PATCH v6 28/34] arm_mpam: Consider overflow in bandwidth counter state Date: Wed, 19 Nov 2025 12:22:58 +0000 Message-ID: <20251119122305.302149-29-ben.horgan@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251119122305.302149-1-ben.horgan@arm.com> References: <20251119122305.302149-1-ben.horgan@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251119_122605_161405_3F1F01AB X-CRM114-Status: GOOD ( 14.94 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Use the overflow status bit to track overflow on each bandwidth counter read and add the counter size to the correction when overflow is detected. This assumes that only a single overflow has occurred since the last read of the counter. Overflow interrupts, on hardware that supports them could be used to remove this limitation. Cc: Zeng Heng Reviewed-by: Gavin Shan Reviewed-by: Zeng Heng Reviewed-by: Jonathan Cameron Reviewed-by: Shaopeng Tan Reviewed-by: Fenghua Yu Tested-by: Carl Worth Tested-by: Gavin Shan Tested-by: Zeng Heng Tested-by: Shaopeng Tan Tested-by: Hanjun Guo Signed-off-by: Ben Horgan --- drivers/resctrl/mpam_devices.c | 24 ++++++++++++++++++++++-- drivers/resctrl/mpam_internal.h | 3 ++- 2 files changed, 24 insertions(+), 3 deletions(-) diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index c8ea37558f69..ecb5ecad50f8 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -985,11 +985,18 @@ static void write_msmon_ctl_flt_vals(struct mon_read *m, u32 ctl_val, } } +static u64 mpam_msmon_overflow_val(enum mpam_device_features type) +{ + /* TODO: scaling, and long counters */ + return BIT_ULL(hweight_long(MSMON___VALUE)); +} + static void __ris_msmon_read(void *arg) { u64 now; bool nrdy = false; bool config_mismatch; + bool overflow; struct mon_read *m = arg; struct mon_cfg *ctx = m->ctx; struct mpam_msc_ris *ris = m->ris; @@ -1011,13 +1018,20 @@ static void __ris_msmon_read(void *arg) * This saves waiting for 'nrdy' on subsequent reads. */ read_msmon_ctl_flt_vals(m, &cur_ctl, &cur_flt); + overflow = cur_ctl & MSMON_CFG_x_CTL_OFLOW_STATUS; + clean_msmon_ctl_val(&cur_ctl); gen_msmon_ctl_flt_vals(m, &ctl_val, &flt_val); config_mismatch = cur_flt != flt_val || cur_ctl != (ctl_val | MSMON_CFG_x_CTL_EN); - if (config_mismatch) + if (config_mismatch) { write_msmon_ctl_flt_vals(m, ctl_val, flt_val); + overflow = false; + } else if (overflow) { + mpam_write_monsel_reg(msc, CFG_MBWU_CTL, + cur_ctl & ~MSMON_CFG_x_CTL_OFLOW_STATUS); + } switch (m->type) { case mpam_feat_msmon_csu: @@ -1037,7 +1051,13 @@ static void __ris_msmon_read(void *arg) mbwu_state = &ris->mbwu_state[ctx->mon]; - /* Include bandwidth consumed before the last hardware reset */ + if (overflow) + mbwu_state->correction += mpam_msmon_overflow_val(m->type); + + /* + * Include bandwidth consumed before the last hardware reset and + * a counter size increment for each overflow. + */ now += mbwu_state->correction; break; default: diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h index 12ce80bc7ff7..218e2f48c7bf 100644 --- a/drivers/resctrl/mpam_internal.h +++ b/drivers/resctrl/mpam_internal.h @@ -211,7 +211,8 @@ struct msmon_mbwu_state { struct mon_cfg cfg; /* - * The value to add to the new reading to account for power management. + * The value to add to the new reading to account for power management, + * and overflow. */ u64 correction; -- 2.43.0