From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: ss -p is much too slow Date: Sat, 31 Jul 2010 19:33:51 -0700 Message-ID: <20100731193351.2b703437@nehalam> References: <20100628.162139.59679342.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: sphink@gmail.com, netdev@vger.kernel.org, stephen.hemminger@vyatta.com To: David Miller Return-path: Received: from mail.vyatta.com ([76.74.103.46]:33579 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753419Ab0HACdx (ORCPT ); Sat, 31 Jul 2010 22:33:53 -0400 In-Reply-To: <20100628.162139.59679342.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 28 Jun 2010 16:21:39 -0700 (PDT) David Miller wrote: > From: Steve Fink > Date: Wed, 9 Jun 2010 11:42:38 -0700 > > > On closer inspection, it appears that ss -p does a quadratic scan. It > > rescans every entry in /proc/*/fd/* repeatedly (once per listening > > port? per process? I don't remember what I figured out.) > > > > I humbly suggest that this is not a good idea. > > Yep, this is junk. Please give this patch a try: > > ss: Avoid quadradic complexity with '-p' > > Scan the process list of open sockets once, and store in a hash > table to be used by subsequent find_user() calls. > > Reported-by: Steve Fink > Signed-off-by: David S. Miller Applied --