From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Ray Bryant" Subject: Re: [PATCH/RFC] Shared page tables Date: Mon, 30 Jan 2006 12:46:24 -0600 References: <43DAA3C9.9070105@us.ibm.com> In-Reply-To: <43DAA3C9.9070105@us.ibm.com> MIME-Version: 1.0 Message-ID: <200601301246.27455.raybry@mpdtxmail.amd.com> Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: owner-linux-mm@kvack.org Return-Path: To: Brian Twichell Cc: Hugh Dickins , Dave McCracken , Andrew Morton , Linux Kernel , Linux Memory Management List-ID: On Friday 27 January 2006 16:50, Brian Twichell wrote: > > Hi, > > We collected more granular performance data for the ppc64/hugepage case. > > CPI decreased by 3% when shared pagetables were used. Underlying this was > a 7% decrease in the overall TLB miss rate. The TLB miss rate for > hugepages decreased 39%. TLB miss rates are calculated per instruction > executed. > Interesting. Do you know if Dave's patch supports sharing of pte's for 2 MB pages on X86_64? Was there a corresponding improvement in overall transaction throughput for the hugetlb, shared pte case? That is, did the 3% improvement in CPI translate to a measurable improvement in the overall OLTP benchmark score? (I'm assuming your 25-50% improvement measurements, as mentioned in a previous note, was for small pages.) > We didn't collect a profile per se, as we would expect a CPI improvement > of this nature to be spread over a significant number of functions, > mostly in user-space. > > Cheers, > Brian > > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org -- Ray Bryant AMD Performance Labs Austin, Tx 512-602-0038 (o) 512-507-7807 (c) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org