From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wenji Wu Subject: RE: [patch 1/4] - Potential performance bottleneck for Linxu TCP Date: Thu, 30 Nov 2006 14:58:00 -0600 Message-ID: References: <20061130202034.GB14696@elte.hu> Reply-To: wenji@fnal.gov Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7BIT Cc: Evgeniy Polyakov , Nick Piggin , David Miller , akpm@osdl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: Received: from mailgw2.fnal.gov ([131.225.111.12]:32896 "EHLO mailgw2.fnal.gov") by vger.kernel.org with ESMTP id S935687AbWK3U6G (ORCPT ); Thu, 30 Nov 2006 15:58:06 -0500 In-reply-to: <20061130202034.GB14696@elte.hu> To: Ingo Molnar Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org >if you still have the test-setup, could you nevertheless try setting the >priority of the receiving TCP task to nice -20 and see what kind of >performance you get? A process with nice of -20 can easily get the interactivity status. When it expires, it still go back to the active array. It just hide the TCP problem, instead of solving it. For a process with nice value of -20, it will have the following advantages over other processes: (1) its timeslice is 800ms, the timeslice of a process with a nice value of 0 is 100ms (2) it has higher priority than other processes (3) it is easier to gain the interactivity status. The chances that the process expires and moves to the expired array with packets within backlog is much reduces, but still has the chance. wenji