From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: [PATCH v5 0/6] enable Memory Bandwidth Monitoring (MBM) for VMs Date: Thu, 22 Jan 2015 07:59:39 +0000 Message-ID: <54C0BBFB0200007800057F60@mail.emea.novell.com> References: <1421839164-26037-1-git-send-email-chao.p.peng@linux.intel.com> <54BF9B7202000078000579DA@mail.emea.novell.com> <20150122011210.GB28428@pengc-linux.bj.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150122011210.GB28428@pengc-linux.bj.intel.com> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Chao Peng Cc: wei.liu2@citrix.com, Ian.Campbell@citrix.com, stefano.stabellini@eu.citrix.com, andrew.cooper3@citrix.com, Ian.Jackson@eu.citrix.com, xen-devel@lists.xen.org, will.auld@intel.com, keir@xen.org List-Id: xen-devel@lists.xenproject.org >>> On 22.01.15 at 02:12, wrote: > On Wed, Jan 21, 2015 at 11:28:34AM +0000, Jan Beulich wrote: >> >>> On 21.01.15 at 12:19, wrote: >> > Changes from v4: >> > * Make the counter read and timestamp read atomic by disable IRQ; >> > * Treat MSR_IA32_TSC as a special case and return NOW() for read path; >> > * Add MBM description in xl command line. >> >> You should really have answered Andrew's question regarding the >> use of NOW() vs RDTSC before posting this new series. > > As I have adopted it so I agree with Andrew's suggestion. NOW() is much > fullfill my requirement. But perhaps not so semantic consistent with > MSR_IA32_TSC? Exactly - I didn't look at the patch itself yet, but at the very least this would need to be very clearly documented in the public header. Jan