Return-path: Received: from mail-gw1-out.broadcom.com ([216.31.210.62]:10169 "EHLO mail-gw1-out.broadcom.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756639AbaHHQpd (ORCPT ); Fri, 8 Aug 2014 12:45:33 -0400 Message-ID: <53E4FEA9.80803@broadcom.com> (sfid-20140808_184606_497048_EB4276B3) Date: Fri, 8 Aug 2014 18:45:29 +0200 From: Arend van Spriel MIME-Version: 1.0 To: Ben Greear , Dave Taht CC: Kalle Valo , "linux-wireless@vger.kernel.org" , ath10k Subject: Re: Reporting firmware stats to ethtool References: <53E3F65D.8080102@candelatech.com> <87wqajz6yg.fsf@kamboji.qca.qualcomm.com> <53E4EFCB.5090501@candelatech.com> <53E4F6B8.50009@candelatech.com> In-Reply-To: <53E4F6B8.50009@candelatech.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 08/08/2014 06:11 PM, Ben Greear wrote: > On 08/08/2014 08:55 AM, Dave Taht wrote: >> On Fri, Aug 8, 2014 at 8:42 AM, Ben Greear wrote: >>> On 08/08/2014 02:06 AM, Kalle Valo wrote: >>>> Ben Greear writes: >>>> >>>>> I'm working on a patch to report the stats seen in debugfs/...ath10k/fw_stats >>>>> as ethtool stats, somewhat similar to how ath9k does it. >>>>> >>>>> I notice that my user-space tool is reporting huge numbers because >>>>> the stats are reset to zero when firmware restarts, and so my tool >>>>> thinks the stats wrapped. >>>>> >>>>> I can fix my tool easily enough, but I first wanted to see if >>>>> anyone had strong feelings about keeping the stats from resetting >>>>> to zero by storing history and calculating diffs in the driver. >>>>> >>>>> I think my preference is to punt this to user-space, but if >>>>> someone feels otherwise, please let me know sooner than later. >>>> >>>> I also prefer to have this in user space, but how does user space know >>>> when the stats have been zeroed? >>> >>> Poll often enough that it cannot increment more than 2 billion (or other large number) >>> between polls, and then if polled value is less than previous (and difference is > 2 billion), >>> we know we had a reset and not a wrap. >> >> I do kind of prefer 64 bit counters in the general case. Nuke it from >> orbit, it's the only way to be sure. > > It's 64-bit to user-space, but that means nothing because firmware > uses 32-bit (or even 16 bit in some cases, probably) internally. > A great deal of counters are the same, so be very careful when > trying to keep long term counters grabbed from firmware/drivers/hardware. > > And, stations come and go when you re-associate, so all sorts of wifi counters > reset themselves all the time... Does ath driver notify mac80211 about firmware restart, ie. through ieee80211_restart_hw(). If only user-space could get that info. Gr. AvS > Thanks, > Ben > >> >>> User-space stats will not be perfect in the case of firmware resets, or resets >>> after the 'large number', but nothing is going to make it perfect, and in >>> practice, this seems good enough. >>> >>> Thanks, >>> Ben >>> >>> -- >>> Ben Greear >>> Candela Technologies Inc http://www.candelatech.com >>> >>> >>> _______________________________________________ >>> ath10k mailing list >>> ath10k@lists.infradead.org >>> http://lists.infradead.org/mailman/listinfo/ath10k >> >> >> > >