Re: [PATCH RFC] [INET]: Get cirtical word in first 64bit of cache line

2012-12-02 Thread Eric Dumazet
On Sun, 2012-12-02 at 21:25 +0800, Ling Ma wrote: > Hi Eric, > > Attached benchmark test-cwf.c(cc -o test-cwf test-cwf.c), the result > shows when last level cache(LLC) miss and CPU fetches data from > memory, critical word as first 64bit member in cache line has better > performance(costs 1582903

Re: [PATCH RFC] [INET]: Get cirtical word in first 64bit of cache line

2012-12-02 Thread Ling Ma
Hi Eric, Attached benchmark test-cwf.c(cc -o test-cwf test-cwf.c), the result shows when last level cache(LLC) miss and CPU fetches data from memory, critical word as first 64bit member in cache line has better performance(costs 158290336 cycles ) than other positions(offset 0x10, costs 164100732

Re: [PATCH RFC] [INET]: Get cirtical word in first 64bit of cache line

2012-11-27 Thread Eric Dumazet
On Tue, 2012-11-27 at 21:48 +0800, Ling Ma wrote: > Ling: in the looking-up routine, hash value is the most important key, > if it is matched, the other values have most possibility to be > satisfied, and CFW is limited by memory bandwidth(64bit usually), so > we only move hash value as critical

Re: [PATCH RFC] [INET]: Get cirtical word in first 64bit of cache line

2012-11-27 Thread Ling Ma
> networking patches should be sent to netdev. > > (I understand this patch is more a generic one, but at least CC netdev) Ling: OK, this is my first inet patch, I will send to netdev later. > You give no performance numbers for this change... Ling: after I get machine, I will send out test result

Re: [PATCH RFC] [INET]: Get cirtical word in first 64bit of cache line

2012-11-26 Thread Ben Hutchings
On Sun, 2012-11-25 at 22:44 -0800, Eric Dumazet wrote: > On Mon, 2012-11-26 at 11:29 +0800, ling.ma.prog...@gmail.com wrote: > > From: Ma Ling > > > > In order to reduce memory latency when last level cache miss occurs, > > modern CPUs i.e. x86 and arm introduced Critical Word First(CWF) or > > E

Re: [PATCH RFC] [INET]: Get cirtical word in first 64bit of cache line

2012-11-25 Thread Eric Dumazet
On Mon, 2012-11-26 at 11:29 +0800, ling.ma.prog...@gmail.com wrote: > From: Ma Ling > > In order to reduce memory latency when last level cache miss occurs, > modern CPUs i.e. x86 and arm introduced Critical Word First(CWF) or > Early Restart(ER) to get data ASAP. For CWF if critical word is firs

[PATCH RFC] [INET]: Get cirtical word in first 64bit of cache line

2012-11-25 Thread ling . ma . program
From: Ma Ling In order to reduce memory latency when last level cache miss occurs, modern CPUs i.e. x86 and arm introduced Critical Word First(CWF) or Early Restart(ER) to get data ASAP. For CWF if critical word is first member in cache line, memory feed CPU with critical word, then fill others d