From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Kirby Subject: Re: Route cache performance Date: Wed, 7 Sep 2005 09:28:54 -0700 Message-ID: <20050907162854.GB24735@netnation.com> References: <20050823190852.GA20794@netnation.com> <17163.32645.202453.145416@robur.slu.se> <20050824000158.GA8137@netnation.com> <20050825181111.GB14336@netnation.com> <20050825200543.GA6612@yakov.inr.ac.ru> <20050825212211.GA23384@netnation.com> <20050826115520.GA12351@yakov.inr.ac.ru> <17167.29239.469711.847951@robur.slu.se> <20050906235700.GA31820@netnation.com> <17182.64751.340488.996748@robur.slu.se> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Alexey Kuznetsov , Eric Dumazet , netdev@oss.sgi.com Return-path: To: Robert Olsson Content-Disposition: inline In-Reply-To: <17182.64751.340488.996748@robur.slu.se> Sender: netdev-bounce@oss.sgi.com Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org On Wed, Sep 07, 2005 at 04:45:03PM +0200, Robert Olsson wrote: > Packet processing happens in RX_SOFIRQ. NAPI or non-NAPI is no difference > with RCU deferred delete this should happen by the RCU-tasklet when > tasklets are run after the real SOFTIRQ's. > > There is a limit for RCU work... maxbatch it's set to 10 you could back > out the patch and try increase it 1000/10000 so we know this not prevent > the freeing of entries. Yes, setting maxbatch to 10000 also results in working gc, though routing throughput is about 5.7% higher when just calling dst_free directly. > Also RCU clearly states that is should be used in read-mostly situations > rDoS is outside this scope. Anyway it would be interesting to understand > what's going on. There was discussion about this before (recycling of existing entries is also now impossible, as compared with 2.4). It's a shame that this win for the normal case also hurts the DoS case...and it really hurts when the when the DoS case is the normal case. Simon-