From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A0081C433F5 for ; Mon, 6 Dec 2021 10:03:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=H99BBFsGRBmf4zl4G6yuQRTtN4lmYFGVrdNVQGkwKNM=; b=lYopDUNH+Q6H3M E6CwmnhE7VEXN2oVBwNEewQTm7mZM2dRCHXFICDF4jPjHRamMibbfeEjfNmzywHwNZ1Abb+SWDdjw 6jUGBY4KEhni89tDEo8CPOtT/K1R7GCH+wrPPIrW5NS1Cdgw1k+eEpewXCXrOdBOg7Y+NFyi1QOPq U0sLKRKYQUKR7dUkt/0FEmieXzG1ei441Q2CLXAk95DoyLlaKZcRjk7J7eru6NTOmKDEXQBwSpv45 Z/P4ZAcmoI6Rx0zjj9wIZ22+0Lu/WpcBUYdOU478uLOhZpXfpBw7d/glZZTWgxk4p2U5hOb5Iew4U MqgWwdFVW1+rN/W0FpWg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1muAoN-003FKN-VF; Mon, 06 Dec 2021 10:01:32 +0000 Received: from mout.kundenserver.de ([212.227.126.134]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1muAoG-003FIL-Cs for linux-arm-kernel@lists.infradead.org; Mon, 06 Dec 2021 10:01:26 +0000 Received: from mail-wr1-f45.google.com ([209.85.221.45]) by mrelayeu.kundenserver.de (mreue011 [213.165.67.97]) with ESMTPSA (Nemesis) id 1MJVY8-1n9Ujq1ca0-00JntO for ; Mon, 06 Dec 2021 11:01:22 +0100 Received: by mail-wr1-f45.google.com with SMTP id d9so21224694wrw.4 for ; Mon, 06 Dec 2021 02:01:22 -0800 (PST) X-Gm-Message-State: AOAM532ka4PNmPVa350fk+OsZop8BBLW+Xq/fOzJV/2lA9sz+MHyiG0g ovne+eNj8WW2O1ij9k1NFd0E4VjD2LOqbh1RX2U= X-Google-Smtp-Source: ABdhPJzK344dYgqqfzp94G+JGpMAcIVesiyoKyE+J1TuWbu6tT5SKZ+BIEtzC2v8Q05uMleLTlgzpaYZiFmuZWtba64= X-Received: by 2002:adf:d091:: with SMTP id y17mr44249813wrh.418.1638784881789; Mon, 06 Dec 2021 02:01:21 -0800 (PST) MIME-Version: 1.0 References: <99ecc64c6da3abb3ea2930082c40f1820655664c.1638275062.git.quic_saipraka@quicinc.com> <0cd0bc8c-e3db-b3fb-5be4-c619d1d5d633@quicinc.com> In-Reply-To: <0cd0bc8c-e3db-b3fb-5be4-c619d1d5d633@quicinc.com> From: Arnd Bergmann Date: Mon, 6 Dec 2021 11:01:05 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCHv5 4/4] asm-generic/io: Add logging support for MMIO accessors To: Sai Prakash Ranjan Cc: Arnd Bergmann , Will Deacon , Catalin Marinas , Steven Rostedt , Marc Zyngier , gregkh , Linux Kernel Mailing List , Linux ARM , linux-arm-msm , quic_psodagud@quicinc.com X-Provags-ID: V03:K1:waA7up1rVRCZvekJv4mTXEghqp5aFdLoiO8dqa3KTnYiLH+jCZa jEl2eezLltTeYOsxIATVw0s8HUFtP7usU15fZbA0w1mqq57Nfc2td8MI0cW8D98dfrCMGCE HRUG2TsroFKDLsqjmEkU0biO23o4wSs8ML50QfgQUGfyTzc818MLGGzaYjbNXCDgnfmAUF1 BamNie2SNZcPgHFBH0lpw== X-UI-Out-Filterresults: notjunk:1;V03:K0:YgOSJanPurQ=:kAY6e9aRiqUhvjlt4nqltu lNRnBd57HM7RnXxAqpwLoSo6mPOp59rUyVOdooEi7ntht1RcfO/3q4EoehQ9AV2aeY8no9Zk+ MqnhprUAVbs71MpTHUFxt1V5TQDqE4S/R0TOSYpcXdhSwcvN8BTGsSqyXqXA/J2vqAoYUrgqK SbbOsja92DLeBYT+PWVzWfftKPvv0WXLhIiFlIKsRwEC+6IOOk4vc9g71ChGsPjeCeg0BSEe/ TebsTWxvKdq8LRTcjftR3W5es9gUTy+/PavWyd2lirlOBPZNgNeezvj2M25fL1KjJaRkzGOMR 4KX4LjO1vglCY3w833bBCw1U6me29Imxsko50l/gbDGyNdlXoac5d/QscrPC2Gs/gEX4T6S6e HQJOnH6orSvp31igp88XpOrtd6JtGy7WeGgLYTf73ZhiMg06aLIz9/wXmPu0wXuQvUzCmZXOd Sh8KHYMYX1ReeDfaSQM2iDeirATkmzRPX5Cx8Xao/RH8/gO0fyC9GfuA1MNyomy87hKbZJvow BJfe6QUDT5UWiUqsZhipJGSA6PM2A5cgpvpxtA9NSqTMtEzpQ+jT7NQUSGikV95NCc/Zpfjmc dOFlSuMPXtVE16DhYqVbi7mQEu0WHizRe9QmC2BwmWN1YWkbDDwyO2orR0lQSf21BsTQigykZ 7yX6kqcmrvdJ9Oy2NayUuweQzRajzXQHgJSswTS5JCU5sCxD176LxrH3G6j1uJ+EpPB0jWIhu Z9qrct+TPnTlcB3kwtkHFoZdbMrQ560HtNzWuUVslESl9FF9AcKmMA6wDboCshSGODNTuwlpu g7sIsqFPYz61AA9Er7nkh42fl5tXKLmwZXQv2hQ75XyoWjvBmE= X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211206_020124_783502_16E81590 X-CRM114-Status: GOOD ( 16.98 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Dec 6, 2021 at 10:52 AM Sai Prakash Ranjan wrote: > > Yes just the trace after read/write won't serve our usecase where we > expect crashes/hangs on accessing > these registers but internally we did have a log_post_read_mmio() as > well, if it is useful then I can add it. Are there any downsides to tracing both before and after, besides another growth in binary size? Aside from the 'value', that would also allow measuring the time it takes to complete a readl(), which may be valuable for other users as these can be significant. Not sure how to best do that that, we could return a timestamp from the 'before' tracepoint and pass it into the 'after' tracepoint in order to log the difference, or just rely on calculating the differences in user space based on the log. For the 'write' style accessors, the timing data would be less interesting, at least for posted PCI transactions, but it may be helpful to do the same for symmetry reasons. Arnd _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel