Return-path: Received: from mail-pa0-f53.google.com ([209.85.220.53]:33425 "EHLO mail-pa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751009AbaIBHb6 (ORCPT ); Tue, 2 Sep 2014 03:31:58 -0400 Received: by mail-pa0-f53.google.com with SMTP id fa1so14161813pad.12 for ; Tue, 02 Sep 2014 00:31:57 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1409597534.2703.9.camel@jlt4.sipsolutions.net> References: <1409597534.2703.9.camel@jlt4.sipsolutions.net> Date: Tue, 2 Sep 2014 09:31:56 +0200 Message-ID: (sfid-20140902_093201_557380_A8256D8F) Subject: Re: wmediumd performance penalty From: Dani Camps To: Johannes Berg Cc: linux-wireless@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: Hi, I am running on a virtual machine with Ubuntu. Does mac80211_hwsim not schedule the packet reception time to the other radio(s) according to the PHY rate in the packet in order to simulate transmission time over the air ? Best Regards Daniel On Mon, Sep 1, 2014 at 8:52 PM, Johannes Berg wrote: > On Mon, 2014-09-01 at 17:38 +0200, Dani Camps wrote: >> Dear all, >> >> I am testing a simple 1-hop mesh network over wmediumd. The PHY rate I >> have configured is 54 Mbps, and there is no loss, however the max >> throughput I get is around 14 Mbps. Without wmediumd I get around 30 >> Mbps, which seems reasonable given the 54 PHY rate. As I noted above >> there is no loss probability configured in wmediumd. >> >> My impression is that the performance drop is due to the overhead of >> switching between kernel and user space in wmediumd, however it >> surprises me that the penalty is so high. >> >> Has anyone had a similar experience? Could there be a way to overcome >> this bottleneck? > > What kind of system are you running on? The virtual PHY rate isn't taken > into account at all, so you should see far higher performance. > > johannes >