From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guennadi Liakhovetski Subject: Re: [RFC 11/12] rpmsg: increase buffer size and reduce buffer number Date: Fri, 5 Jun 2020 08:37:18 +0200 Message-ID: <20200605063718.GB32302@ubuntu> References: <20200529073722.8184-1-guennadi.liakhovetski@linux.intel.com> <20200529073722.8184-12-guennadi.liakhovetski@linux.intel.com> <20200604195839.GA26734@xps15> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20200604195839.GA26734@xps15> Sender: kvm-owner@vger.kernel.org To: Mathieu Poirier Cc: kvm@vger.kernel.org, linux-remoteproc@vger.kernel.org, virtualization@lists.linux-foundation.org, sound-open-firmware@alsa-project.org, Pierre-Louis Bossart , Liam Girdwood , "Michael S. Tsirkin" , Jason Wang , Ohad Ben-Cohen , Bjorn Andersson List-Id: virtualization@lists.linuxfoundation.org Hi Mathieu, On Thu, Jun 04, 2020 at 01:58:39PM -0600, Mathieu Poirier wrote: > Hi Guennadi, > > On Fri, May 29, 2020 at 09:37:21AM +0200, Guennadi Liakhovetski wrote: > > It is hard to imagine use-cases where 512 buffers would really be > > needed, whereas 512 bytes per buffer might be too little. Change this > > to use 16 16KiB buffers instead. > > > > Signed-off-by: Guennadi Liakhovetski > > --- > > include/linux/virtio_rpmsg.h | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/include/linux/virtio_rpmsg.h b/include/linux/virtio_rpmsg.h > > index 679be8b..1add468 100644 > > --- a/include/linux/virtio_rpmsg.h > > +++ b/include/linux/virtio_rpmsg.h > > @@ -72,8 +72,8 @@ enum rpmsg_ns_flags { > > * can change this without changing anything in the firmware of the remote > > * processor. > > */ > > -#define MAX_RPMSG_NUM_BUFS 512 > > -#define MAX_RPMSG_BUF_SIZE 512 > > +#define MAX_RPMSG_NUM_BUFS (512 / 32) > > +#define MAX_RPMSG_BUF_SIZE (512 * 32) > > These have been a standard in the rpmsg protocol since the inception of the > subsystem 9 years ago and can't be changed without serious impact to existing > implementations. Yes, I expected this to raise complaints. I just modified them to be able to run my code, but a better solution is needed for sure. > I suggest to dynamically set the number and size of the buffers to use > based on the value of virtio_device_id::device. To do that please spin > off a new function, something like rpmsg_get_buffer_size(), and in there use > the device ID to fetch the numbers based on vdev->id->device. That way the > rpmsg driver can be used by multiple clients and the specifics of the buffers > adjusted without impact to other users. I'll look into this! Thanks Guennadi > Thanks, > Mathieu > > > > > /* Address 53 is reserved for advertising remote services */ > > #define RPMSG_NS_ADDR 53 > > -- > > 1.9.3 > >