From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin LaHaise Subject: Re: [patch 1/4] net: percpufy frequently used vars -- add percpu_counter_mod_bh Date: Wed, 8 Mar 2006 16:17:33 -0500 Message-ID: <20060308211733.GA5410@kvack.org> References: <20060308015808.GA9062@localhost.localdomain> <20060308015934.GB9062@localhost.localdomain> <20060307181301.4dd6aa96.akpm@osdl.org> <20060308202656.GA4493@localhost.localdomain> <20060308203642.GZ5410@kvack.org> <20060308210726.GD4493@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andrew Morton , linux-kernel@vger.kernel.org, davem@davemloft.net, netdev@vger.kernel.org, shai@scalex86.org Return-path: To: Ravikiran G Thirumalai Content-Disposition: inline In-Reply-To: <20060308210726.GD4493@localhost.localdomain> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Wed, Mar 08, 2006 at 01:07:26PM -0800, Ravikiran G Thirumalai wrote: > But on non x86, local_bh_disable() is gonna be cheaper than a cli/atomic op no? > (Even if they were switched over to do local_irq_save() and > local_irq_restore() from atomic_t's that is). It's still more expensive than local_t. > And if we use local_t, we will add the overhead for the non bh > percpu_counter_mod for non x86 arches. Last time I checked, all the major architectures had efficient local_t implementations. Most of the RISC CPUs are able to do a load / store conditional implementation that is the same cost (since memory barriers tend to be explicite on powerpc). So why not use it? -ben -- "Time is of no importance, Mr. President, only life is important." Don't Email: .