Date: Thu, 19 Apr 2012 23:17:41 +0200 From: "K. Macy" <kmacy@freebsd.org> To: Andre Oppermann <andre@freebsd.org> Cc: Luigi Rizzo <rizzo@iet.unipi.it>, current@freebsd.org, net@freebsd.org Subject: Re: Some performance measurements on the FreeBSD network stack Message-ID: <CAHM0Q_NwvLVFgeE3xsaf8nO1Nusm4QBp7eRuMn=UuNWWFp0vnw@mail.gmail.com> In-Reply-To: <4F907FB4.3080400@freebsd.org> References: <20120419133018.GA91364@onelab2.iet.unipi.it> <4F907011.9080602@freebsd.org> <20120419204622.GA94904@onelab2.iet.unipi.it> <CAHM0Q_M4wcEiWGkjWxE1OjLeziQN0vM%2B4_EYS_WComZ6=j5xhA@mail.gmail.com> <4F907FB4.3080400@freebsd.org>
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>> This only helps if your flows aren't hitting the same rtentry. >> Otherwise you still convoy on the lock for the rtentry itself to >> increment and decrement the rtentry's reference count. > > > The rtentry lock isn't obtained anymore. =A0While the rmlock read > lock is held on the rtable the relevant information like ifp and > such is copied out. =A0No later referencing possible. =A0In the end > any referencing of an rtentry would be forbidden and the rtentry > lock can be removed. =A0The second step can be optional though. Can you point me to a tree where you've made these changes? >>> i was wondering, is there a way (and/or any advantage) to use the >>> fastforward code to look up the route for locally sourced packets ? >>> >> >> If the number of peers is bounded then you can use the flowtable. Max >> PPS is much higher bypassing routing lookup. However, it doesn't scale >> to arbitrary flow numbers. > > > In theory a rmlock-only lookup into a default-route only routing > table would be faster than creating a flow table entry for every > destination. =A0It a matter of churn though. =A0The flowtable isn't > lockless in itself, is it? It is. In a steady state where the working set of peers fits in the table it should be just a simple hash of the ip and then a lookup. -Kip --=20 =A0 =A0=93The real damage is done by those millions who want to 'get by.' The ordinary men who just want to be left in peace. Those who don=92t want their little lives disturbed by anything bigger than themselves. Those with no sides and no causes. Those who won=92t take measure of their own strength, for fear of antagonizing their own weakness. Those who don=92t like to make waves=97or enemies. =A0 =A0Those for whom freedom, honour, truth, and principles are only literature. Those who live small, love small, die small. It=92s the reductionist approach to life: if you keep it small, you=92ll keep it under control. If you don=92t make any noise, the bogeyman won=92t find you. =A0 =A0But it=92s all an illusion, because they die too, those people who roll up their spirits into tiny little balls so as to be safe. Safe?! >From what? Life is always on the edge of death; narrow streets lead to the same place as wide avenues, and a little candle burns itself out just like a flaming torch does. =A0 =A0I choose my own way to burn.=94 =A0 =A0Sophie Scholl
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