From mboxrd@z Thu Jan 1 00:00:00 1970 From: "majun (Euler7)" Subject: Re: [RFC PATCH 0/3] Add a new flag for ITS device to control indirect route Date: Fri, 2 Dec 2016 17:29:50 +0800 Message-ID: <58413F0E.3030604@huawei.com> References: <1480578360-9268-1-git-send-email-majun258@huawei.com> <3ce161a7-ee63-a018-4a75-9e7520143d97@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: Received: from szxga02-in.huawei.com ([119.145.14.65]:39052 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751731AbcLBJaV (ORCPT ); Fri, 2 Dec 2016 04:30:21 -0500 In-Reply-To: <3ce161a7-ee63-a018-4a75-9e7520143d97@arm.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Marc Zyngier , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, robert.moore@intel.com, lenb@kernel.org, lv.zheng@intel.com, rafael.j.wysocki@intel.com, devel@acpica.org, mark.rutland@arm.com, robh+dt@kernel.org, jason@lakedaemon.net Cc: majun258@huawei.com, dingtianhong@huawei.com, guohanjun@huawei.com 在 2016/12/1 17:07, Marc Zyngier 写道: > On 01/12/16 07:45, Majun wrote: >> From: MaJun >> >> For current ITS driver, two level table (indirect route) is enabled when the memory used >> for LPI route table over the limit(64KB * 2) size. But this function impact the >> performance of LPI interrupt actually because need more time to look up the table. > > Are you implying that your ITS doesn't have a cache to lookup the most > active devices, hence performing a full lookup on each interrupt? Our ITS chip has the cache with depth 64. But this seems not enough for some scenario,espeically on virtulization platform. > > Anyway, doing this as a DT quirk doesn't feel right. Please use the ITS > quirk infrastructure. If there is no other better solutions, I will do this. Thanks! Majun > > Thanks, > > M. >