From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f176.google.com (mail-pg1-f176.google.com [209.85.215.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8783B72 for ; Thu, 8 Jul 2021 21:42:27 +0000 (UTC) Received: by mail-pg1-f176.google.com with SMTP id k20so795350pgg.7 for ; Thu, 08 Jul 2021 14:42:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=sF2SLv1J75sp7+9Z1D9xVZ2DZMuDJ4EIVCMBTYYdpaE=; b=Aucdo1nfTK9WH4YHFO+S0c2jMbiU+rLKBqaY0zjsSpynqLigrfR7DDG70BEKnBjk2L LK0dbFuinG4+S9r2tCykcvamS4XykDOrzg5frGug5aTpIdLpovE/Ug35fY89p5rBOmWn U4AokinMmygIU+via+i9HWoOQbNobN0leqzxTX268f0SkE+gvP4UFJoIk/4IfZ+mZWuw uBw1Ax+QVH9HJWoQYNSax5r4p3wf9EBL60RrHfg1ds7FsTUCgB7uBkgl/58ozBeWrNNW 6oMAbSk4/hKNWHXVnbqKpz22rSPnqQ4sAunLGji7eWAFuN8Csm0fNqSvD21uDgaEWIYM ygCA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=sF2SLv1J75sp7+9Z1D9xVZ2DZMuDJ4EIVCMBTYYdpaE=; b=cFJpLp+lA2nFqXlvyuh3yoMSNO40qUE0+LEUkpdaga5cnBPu8Fe+kvhKDZqqZSuOlC B88sCjPmoQvJg96yfZET340TFat3PFvbmxbmax5Hk9ENpIvRfLoXJ6Q5cSj2DsDlqRke W87+OHGHlTig1sXPAqg1j7j3lwowG9JZUB89AweCvBQx1JY1ra+qiBbn0yyGb7Aw56IH ILRIQgkx9xk2rfnY9b3IDNkJclj6aZK43sNVK4zJNr9slzaL2o6pbZSCNsrJC0vVJABQ axo04rLSwZWt2QfNNsR3CzAKfjlCHg0mtKj35oLqOGC2P3kSalMwXYra19vKWRX2PJdP UjgQ== X-Gm-Message-State: AOAM532jzLf4Ia6VAGv8xPS1FcW8epnUQrEx0scQsAWbrR7ukHEVouRr gTnpe7C/k5v9vd1qCAeyzELE/Fe5JcX0diRiDHuwI0HQk94= X-Google-Smtp-Source: ABdhPJzv3zrUckZX0y97aE7n06bPIRIcPuBnKemI5fQhx9cUbdgi2Ux4cZkkFMY7olUk+eEzHWgEkzDp8Y94hOrUubg= X-Received: by 2002:a63:d54b:: with SMTP id v11mr12860663pgi.450.1625780546940; Thu, 08 Jul 2021 14:42:26 -0700 (PDT) Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20210708183741.2952-1-james.sushanth.anandraj@intel.com> <20210708183741.2952-2-james.sushanth.anandraj@intel.com> In-Reply-To: <20210708183741.2952-2-james.sushanth.anandraj@intel.com> From: Dan Williams Date: Thu, 8 Jul 2021 14:42:16 -0700 Message-ID: Subject: Re: [PATCH v1 1/4] Documentation/pcdctl: Add documentation for pcdctl tool and commands To: James Anandraj Cc: Linux NVDIMM Content-Type: text/plain; charset="UTF-8" On Thu, Jul 8, 2021 at 11:38 AM James Anandraj wrote: [..] > diff --git a/Documentation/pcdctl/theory-of-operation.txt b/Documentation/pcdctl/theory-of-operation.txt > new file mode 100644 > index 0000000..b363195 > --- /dev/null > +++ b/Documentation/pcdctl/theory-of-operation.txt > @@ -0,0 +1,28 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +THEORY OF OPERATION > +------------------- > +A region is persistent memory from one or more non-volatile memory devices that > +is mapped into the system physical address (SPA) space. For some device vendors, > +reconfiguring regions is a multi-step process as follows. > +1. Generate a new region configuration request using this command. > +2. Reset the platform. > +3. Platform firmware (BIOS) processes the region configuration request and > +presents the new region configuration via ACPI NFIT tables. The status of this > +BIOS operation can be retrieved using the pcdctl-list command. > + > +Region types are as follows: > +1. Interleaved Persistent Memory Region (iso-pmem) > +This is a persistent memory region that utilizes hardware interleaving across > +non-volatile memory devices. > +2. Non-Interleaved Persistent Memory Region (pmem) > +This is a persistent memory region that does not utilize hardware interleaving > +across non-volatile memory devices. "iso-pmem" and "pmem" are not immediately obvious names for interleaved and non-interleaved pmem. Even "interleave" is not a great term unless the user is familiar with the operation of the memory controller. How about "performance-pmem" and "fault-isolation-pmem" as that is the question that is being asked of the user? I.e. do you want to configure pmem to maximize bandwidth, or do you want to configure pmem to maximize the isolation and resiliency to faults in individual modules.