From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:45284 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726219AbfEIVoQ (ORCPT ); Thu, 9 May 2019 17:44:16 -0400 Date: Thu, 9 May 2019 17:42:33 -0400 From: "Theodore Ts'o" Subject: Re: [PATCH v2 00/17] kunit: introduce KUnit, the Linux kernel unit testing framework Message-ID: <20190509214233.GA20877@mit.edu> References: <54940124-50df-16ec-1a32-ad794ee05da7@gmail.com> <20190507080119.GB28121@kroah.com> <20190509015856.GB7031@mit.edu> <580e092f-fa4e-eedc-9e9a-a57dd085f0a6@gmail.com> <20190509032017.GA29703@mit.edu> <7fd35df81c06f6eb319223a22e7b93f29926edb9.camel@oracle.com> <20190509133551.GD29703@mit.edu> <875c546d-9713-bb59-47e4-77a1d2c69a6d@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <875c546d-9713-bb59-47e4-77a1d2c69a6d@gmail.com> Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: Frank Rowand Cc: Tim.Bird@sony.com, knut.omang@oracle.com, gregkh@linuxfoundation.org, brendanhiggins@google.com, keescook@google.com, kieran.bingham@ideasonboard.com, mcgrof@kernel.org, robh@kernel.org, sboyd@kernel.org, shuah@kernel.org, devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org, kunit-dev@googlegroups.com, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-nvdimm@lists.01.org, linux-um@lists.infradead.org, Alexander.Levin@microsoft.com, amir73il@gmail.com, dan.carpenter@oracle.com, dan.j.williams@intel.com, daniel@ffwll.ch, jdike@addtoit.com, joel@jms.id.au, julia.lawall@lip6.fr, khilman@baylibre.com, logang@deltatee.com, mpe@ellerman.id.au, pmladek@suse.com, richard@nod.at, rientjes@google.com, rostedt@goodmis.org, wfg@linux.intel.com On Thu, May 09, 2019 at 11:12:12AM -0700, Frank Rowand wrote: > > "My understanding is that the intent of KUnit is to avoid booting a kernel on > real hardware or in a virtual machine. That seems to be a matter of semantics > to me because isn't invoking a UML Linux just running the Linux kernel in > a different form of virtualization? > > So I do not understand why KUnit is an improvement over kselftest. > > ... > > What am I missing?" One major difference: kselftest requires a userspace environment; it starts systemd, requires a root file system from which you can load modules, etc. Kunit doesn't require a root file system; doesn't require that you start systemd; doesn't allow you to run arbitrary perl, python, bash, etc. scripts. As such, it's much lighter weight than kselftest, and will have much less overhead before you can start running tests. So it's not really the same kind of virtualization. Does this help? - Ted