From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zoltan Kiss Subject: Re: [PATCH] tracing/events: Add bounce tracing to swiotbl-xen Date: Wed, 4 Sep 2013 21:10:50 +0100 Message-ID: <522793CA.3060002@citrix.com> References: <1377208048-8963-1-git-send-email-zoltan.kiss@citrix.com> <20130823125533.GC14306@konrad-lan.dumpdata.com> <5224D0D6.40908@citrix.com> <20130903124237.GB9870@konrad-lan.dumpdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130903124237.GB9870@konrad-lan.dumpdata.com> Sender: linux-kernel-owner@vger.kernel.org To: Konrad Rzeszutek Wilk Cc: Jeremy Fitzhardinge , Steven Rostedt , Frederic Weisbecker , Ingo Molnar , linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, virtualization@lists.linux-foundation.org List-Id: xen-devel@lists.xenproject.org On 03/09/13 13:42, Konrad Rzeszutek Wilk wrote: > Correct. The double buffering code is being run in lib/swiotlb.c not the > xen-swiotlb.c. Hence the question of why not move the tracing in there. I've put the trace to both locations before swiotlb_tbl_map_single is called, so the same tracer will be hit both with classic and Xen SWIOTLB. I used 2 different place instead of calling from swiotlb_tbl_map_single because I want to print out dev_addr, and it's calculated differently. > Yes. And please (if it adds a benefit) also for unmap/sync which can trigger > the bounce buffer. > > Or if it makes sense just for the bounce buffer copying - then just > leave it at that. Thanks. For me the relevant event was to see when we start to do bounce buffering. When does it end, or when syncing happens is a different thing. If someone is interested, they can easily extend this patch with that. However one question bothers me: why ftrace doesn't trace these functions? They are not inlined, static, or marked as notrace. Regards, Zoli