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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1CF07C4332F for ; Fri, 4 Feb 2022 14:15:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357147AbiBDOPF (ORCPT ); Fri, 4 Feb 2022 09:15:05 -0500 Received: from smtp-out2.suse.de ([195.135.220.29]:58928 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240322AbiBDOPE (ORCPT ); Fri, 4 Feb 2022 09:15:04 -0500 Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 07F2D1F38F; Fri, 4 Feb 2022 14:15:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1643984103; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=x7Xef+LHLUOFJjJq2zLv1fwP3izEqk/6tFjtKVXKieo=; b=d7Njk3prV8hRniilXg/s9deMKAnPYFs5GdS70Bmm+70rRO+ce6K48fI4rpFMhZZ6lDtbxb ZJKCKTjLIvqpo41/2xP6jQUrmQnWomfOOWz4nxZh4VEpa5JMi3hKS9x1ufRYkQxx1KYF8R X2KfxyuIlFXKhCENQvezESv5XTR/EC0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1643984103; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=x7Xef+LHLUOFJjJq2zLv1fwP3izEqk/6tFjtKVXKieo=; b=+An9ufe0fv2coZRexo04U1M024Rg6ufMB1+/yhsOF1ytaTXPzfgX8IJsWFnIOkqEihajpN BnNcKVaccT4T6SDw== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id B8AFF13AE2; Fri, 4 Feb 2022 14:15:02 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id WXHDLOY0/WFfCQAAMHmgww (envelope-from ); Fri, 04 Feb 2022 14:15:02 +0000 Message-ID: Date: Fri, 4 Feb 2022 15:15:02 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.0 Content-Language: en-US To: Chaitanya Kulkarni , =?UTF-8?Q?Javier_Gonz=c3=a1lez?= Cc: Damien Le Moal , Luis Chamberlain , Mikulas Patocka , "linux-block@vger.kernel.org" , Keith Busch , Adam Manzanares , "linux-scsi@vger.kernel.org" , "dm-devel@redhat.com" , "linux-nvme@lists.infradead.org" , linux-fsdevel , Jens Axboe , "msnitzer@redhat.com >> msnitzer@redhat.com" , Bart Van Assche , "martin.petersen@oracle.com >> Martin K. Petersen" , "roland@purestorage.com" , Christoph Hellwig , "Frederick.Knight@netapp.com" , "zach.brown@ni.com" , "osandov@fb.com" , "lsf-pc@lists.linux-foundation.org" , "djwong@kernel.org" , "josef@toxicpanda.com" , "clm@fb.com" , "dsterba@suse.com" , "tytso@mit.edu" , "jack@suse.com" , Kanchan Joshi References: <270f30df-f14c-b9e4-253f-bff047d32ff0@nvidia.com> <20220203153843.szbd4n65ru4fx5hx@garbanzo> <20220203165238.GA142129@dhcp-10-100-145-180.wdc.com> <20220203195155.GB249665@bgt-140510-bm01> <863d85e3-9a93-4d8c-cf04-88090eb4cc02@nvidia.com> <2bbed027-b9a1-e5db-3a3d-90c40af49e09@opensource.wdc.com> <9d5d0b50-2936-eac3-12d3-a309389e03bf@nvidia.com> <20220204082445.hczdiy2uhxfi3x2g@ArmHalley.local> <4d5410a5-93c3-d73c-6aeb-2c1c7f940963@nvidia.com> From: Hannes Reinecke Subject: Re: [RFC PATCH 3/3] nvme: add the "debug" host driver In-Reply-To: <4d5410a5-93c3-d73c-6aeb-2c1c7f940963@nvidia.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 2/4/22 10:58, Chaitanya Kulkarni wrote: > On 2/4/22 12:24 AM, Javier González wrote: [ .. ] >> For a software-only solution, we have experimented with something >> similar to the nvme-debug code tha Mikulas is proposing. Adam pointed to >> the nvme-loop target as an alternative and this seems to work pretty >> nicely. I do not believe there should be many changes to support copy >> offload using this. >> > > If QEMU is so incompetent then we need to add every big feature into > the NVMeOF test target so that we can test it better ? is that what > you are proposing ? since if we implement one feature, it will be > hard to nack any new features that ppl will come up with > same rationale "with QEMU being slow and hard to test race > conditions etc .." > How would you use qemu for bare-metal testing? > and if that is the case why we don't have ZNS NVMeOF target > memory backed emulation ? Isn't that a bigger and more > complicated feature than Simple Copy where controller states > are involved with AENs ? > > ZNS kernel code testing is also done on QEMU, I've also fixed > bugs in the ZNS kernel code which are discovered on QEMU and I've not > seen any issues with that. Given that simple copy feature is way smaller > than ZNS it will less likely to suffer from slowness and etc (listed > above) in QEMU. > > my point is if we allow one, we will be opening floodgates and we need > to be careful not to bloat the code unless it is _absolutely > necessary_ which I don't think it is based on the simple copy > specification. > I do have a slightly different view on the nvme target code; it should provide the necessary means to test the nvme host code. And simple copy is on of these features, especially as it will operate as an exploiter of the new functionality. Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), GF: Felix Imendörffer 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 us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 DE557C433EF for ; Fri, 4 Feb 2022 14:24:11 +0000 (UTC) Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-25-BOVxiUfpPOeKCRXn8_CqFg-1; Fri, 04 Feb 2022 09:24:09 -0500 X-MC-Unique: BOVxiUfpPOeKCRXn8_CqFg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5987F1923BB8; 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Petersen" , Luis Chamberlain , "jack@suse.com" , linux-fsdevel , "lsf-pc@lists.linux-foundation.org" Subject: Re: [dm-devel] [RFC PATCH 3/3] nvme: add the "debug" host driver X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Transfer-Encoding: base64 Content-Type: text/plain; charset="utf-8"; Format="flowed" T24gMi80LzIyIDEwOjU4LCBDaGFpdGFueWEgS3Vsa2Fybmkgd3JvdGU6Cj4gT24gMi80LzIyIDEy OjI0IEFNLCBKYXZpZXIgR29uesOhbGV6IHdyb3RlOgpbIC4uIF0KPj4gRm9yIGEgc29mdHdhcmUt b25seSBzb2x1dGlvbiwgd2UgaGF2ZSBleHBlcmltZW50ZWQgd2l0aCBzb21ldGhpbmcKPj4gc2lt aWxhciB0byB0aGUgbnZtZS1kZWJ1ZyBjb2RlIHRoYSBNaWt1bGFzIGlzIHByb3Bvc2luZy4gQWRh bSBwb2ludGVkIHRvCj4+IHRoZSBudm1lLWxvb3AgdGFyZ2V0IGFzIGFuIGFsdGVybmF0aXZlIGFu ZCB0aGlzIHNlZW1zIHRvIHdvcmsgcHJldHR5Cj4+IG5pY2VseS4gSSBkbyBub3QgYmVsaWV2ZSB0 aGVyZSBzaG91bGQgYmUgbWFueSBjaGFuZ2VzIHRvIHN1cHBvcnQgY29weQo+PiBvZmZsb2FkIHVz aW5nIHRoaXMuCj4+Cj4gCj4gSWYgUUVNVSBpcyBzbyBpbmNvbXBldGVudCB0aGVuIHdlIG5lZWQg dG8gYWRkIGV2ZXJ5IGJpZyBmZWF0dXJlIGludG8KPiB0aGUgTlZNZU9GIHRlc3QgdGFyZ2V0IHNv IHRoYXQgd2UgY2FuIHRlc3QgaXQgYmV0dGVyID8gaXMgdGhhdCB3aGF0Cj4geW91IGFyZSBwcm9w b3NpbmcgPyBzaW5jZSBpZiB3ZSBpbXBsZW1lbnQgb25lIGZlYXR1cmUsIGl0IHdpbGwgYmUKPiBo YXJkIHRvIG5hY2sgYW55IG5ldyBmZWF0dXJlcyB0aGF0IHBwbCB3aWxsIGNvbWUgdXAgd2l0aAo+ IHNhbWUgcmF0aW9uYWxlICJ3aXRoIFFFTVUgYmVpbmcgc2xvdyBhbmQgaGFyZCB0byB0ZXN0IHJh Y2UKPiBjb25kaXRpb25zIGV0YyAuLiIKPiAKCkhvdyB3b3VsZCB5b3UgdXNlIHFlbXUgZm9yIGJh cmUtbWV0YWwgdGVzdGluZz8KCj4gYW5kIGlmIHRoYXQgaXMgdGhlIGNhc2Ugd2h5IHdlIGRvbid0 IGhhdmUgWk5TIE5WTWVPRiB0YXJnZXQKPiBtZW1vcnkgYmFja2VkIGVtdWxhdGlvbiA/IElzbid0 IHRoYXQgYSBiaWdnZXIgYW5kIG1vcmUKPiBjb21wbGljYXRlZCBmZWF0dXJlIHRoYW4gU2ltcGxl IENvcHkgd2hlcmUgY29udHJvbGxlciBzdGF0ZXMKPiBhcmUgaW52b2x2ZWQgd2l0aCBBRU5zID8K PiAKPiBaTlMga2VybmVsIGNvZGUgdGVzdGluZyBpcyBhbHNvIGRvbmUgb24gUUVNVSwgSSd2ZSBh bHNvIGZpeGVkCj4gYnVncyBpbiB0aGUgWk5TIGtlcm5lbCBjb2RlIHdoaWNoIGFyZSBkaXNjb3Zl cmVkIG9uIFFFTVUgYW5kIEkndmUgbm90Cj4gc2VlbiBhbnkgaXNzdWVzIHdpdGggdGhhdC4gR2l2 ZW4gdGhhdCBzaW1wbGUgY29weSBmZWF0dXJlIGlzIHdheSBzbWFsbGVyCj4gdGhhbiBaTlMgaXQg d2lsbCBsZXNzIGxpa2VseSB0byBzdWZmZXIgZnJvbSBzbG93bmVzcyBhbmQgZXRjIChsaXN0ZWQK PiBhYm92ZSkgaW4gUUVNVS4KPiAKPiBteSBwb2ludCBpcyBpZiB3ZSBhbGxvdyBvbmUsIHdlIHdp bGwgYmUgb3BlbmluZyBmbG9vZGdhdGVzIGFuZCB3ZSBuZWVkCj4gdG8gYmUgY2FyZWZ1bCBub3Qg dG8gYmxvYXQgdGhlIGNvZGUgdW5sZXNzIGl0IGlzIF9hYnNvbHV0ZWx5Cj4gbmVjZXNzYXJ5XyB3 aGljaCBJIGRvbid0IHRoaW5rIGl0IGlzIGJhc2VkIG9uIHRoZSBzaW1wbGUgY29weQo+IHNwZWNp ZmljYXRpb24uCj4gCgpJIGRvIGhhdmUgYSBzbGlnaHRseSBkaWZmZXJlbnQgdmlldyBvbiB0aGUg bnZtZSB0YXJnZXQgY29kZTsgaXQgc2hvdWxkIApwcm92aWRlIHRoZSBuZWNlc3NhcnkgbWVhbnMg dG8gdGVzdCB0aGUgbnZtZSBob3N0IGNvZGUuCkFuZCBzaW1wbGUgY29weSBpcyBvbiBvZiB0aGVz ZSBmZWF0dXJlcywgZXNwZWNpYWxseSBhcyBpdCB3aWxsIG9wZXJhdGUgCmFzIGFuIGV4cGxvaXRl ciBvZiB0aGUgbmV3IGZ1bmN0aW9uYWxpdHkuCgpDaGVlcnMsCgpIYW5uZXMKLS0gCkRyLiBIYW5u ZXMgUmVpbmVja2UJCSAgICAgICAgICAgS2VybmVsIFN0b3JhZ2UgQXJjaGl0ZWN0CmhhcmVAc3Vz ZS5kZQkJCSAgICAgICAgICAgICAgICAgICs0OSA5MTEgNzQwNTMgNjg4ClNVU0UgU29mdHdhcmUg U29sdXRpb25zIEdlcm1hbnkgR21iSCwgTWF4ZmVsZHN0ci4gNSwgOTA0MDkgTsO8cm5iZXJnCkhS QiAzNjgwOSAoQUcgTsO8cm5iZXJnKSwgR0Y6IEZlbGl4IEltZW5kw7ZyZmZlcgoKCi0tCmRtLWRl dmVsIG1haWxpbmcgbGlzdApkbS1kZXZlbEByZWRoYXQuY29tCmh0dHBzOi8vbGlzdG1hbi5yZWRo YXQuY29tL21haWxtYW4vbGlzdGluZm8vZG0tZGV2ZWw=