From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grygorii Strashko Subject: Re: [PATCH 3/6] net: ethernet: ti: cpts: add support of cpts HW_TS_PUSH Date: Thu, 8 Dec 2016 13:04:11 -0600 Message-ID: <58eea45f-b8fe-6892-e784-b41638c62fd8@ti.com> References: <20161128230428.6872-1-grygorii.strashko@ti.com> <20161128230428.6872-4-grygorii.strashko@ti.com> <20161203232130.GA17944@netboy> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20161203232130.GA17944@netboy> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Richard Cochran Cc: "David S. Miller" , netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Mugunthan V N , Sekhar Nori , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Rob Herring , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Murali Karicheri , Wingman Kwok List-Id: devicetree@vger.kernel.org On 12/03/2016 05:21 PM, Richard Cochran wrote: > On Mon, Nov 28, 2016 at 05:04:25PM -0600, Grygorii Strashko wrote: >> This also change overflow polling period when HW_TS_PUSH feature is >> enabled - overflow check work will be scheduled more often (every >> 200ms) for proper HW_TS_PUSH events reporting. > > For proper reporting, you should make use of the interrupt. The small > fifo (16 iirc) could very well overflow in 200 ms. The interrupt > handler should read out the entire fifo at each interrupt. > huh. Seems this is not really good idea, because MISC Irq will be triggered for *any* CPTS event and there is no way to enable it just for HW_TS_PUSH. So, this doesn't work will with current code for RX/TX timestamping (which uses polling mode). + runtime overhead in net RX/TX caused by triggering more interrupts. May be, overflow check/polling timeout can be made configurable (module parameter). -- regards, -grygorii -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html