Microsoft Becomes Sponsor of Open Source Initiative

Posted Sep 28, 2017 18:06 UTC (Thu) by Cyberax (✭ supporter ✭, #52523)
In reply to: Microsoft Becomes Sponsor of Open Source Initiative by ledow
Parent article: Microsoft Becomes Sponsor of Open Source Initiative

> Kernel work in Azure? Pure self-interest. Now you can run Linux on Windows clouds. Do they do the same they other way?
They do. MS optimized Windows to better work with KVM and XEN.

> Closed-source SQL Server, for a single architecture, without the high-end features, running in a boxed-in "Windows emulation"-like environment.
The Linux-based SQL server has pretty much all of the Windows features except the ones that don't make sene on Linux. It's just as fast (sometimes faster) and feature-complete. It doesn't use any "windows emulation" - it's a simple Linux application, that is easily installed through package managers (there are DEBs and RPMs).

So please, if you want to spread FUD then at least find something that has basis in the reality.

Microsoft Becomes Sponsor of Open Source Initiative

Posted Sep 28, 2017 18:44 UTC (Thu) by pbonzini (subscriber, #60935) [Link]

> MS optimized Windows to better work with KVM and XEN.

No, they didn't. They did provide documentation for the API that the hypervisor has to provide, but the Xen and KVM people implemented them.

And there was nothing to do on Windows, foreign hypervisors simply fake themselves as Hyper-V.

Microsoft Becomes Sponsor of Open Source Initiative

Posted Sep 28, 2017 19:24 UTC (Thu) by evad (guest, #60553) [Link] (3 responses)

Regarding "spreading FUD"...

SQL server is not a simple Linux application. It runs on top of a compatibility layer based on something called "Drawbridge":

"Drawbridge is a research prototype of a new form of virtualization for application sandboxing. Drawbridge combines two core technologies: First, a picoprocess, which is a process-based isolation container with a minimal kernel API surface. Second, a library OS, which is a version of Windows enlightened to run efficiently within a picoprocess."

It is called 'SQLPAL' (the compatibility layer). For all intents and purposes, it emulates/virtualises a Windows interface, and SQL server uses that.

See this article for details: https://techcrunch.com/2017/07/17/how-microsoft-brought-s...

It is NOT a simple Linux application. From its perspective, SQL Server on Linux is actually running on Windows.

Microsoft Becomes Sponsor of Open Source Initiative

Posted Sep 28, 2017 19:34 UTC (Thu) by Cyberax (✭ supporter ✭, #52523) [Link] (2 responses)

Drawbridge is a simple abstraction layer to allow SQL server to share the code between two different platforms, kinda like Apache's APR for example.

The major complication is the behavior of virtual memory and asynchronous IO which work differently in Linux and Windows. SQL server also uses fibers on Windows for its own concurrency management, so they reimplemented this as well. And "picoprocess" is just a BS term for a "thread with some unshared VMAs".

After refactoring, MS SQL actually uses the same architecture on Windows as well. So Windows is now a second-class citizen for MS SQL according to you.

I'm running MS SQL right now, and it is a simple process. It doesn't require anything special, you just run a daemon using systemctl and that's it. Feel free to download a developer version and check it yourself.

Microsoft Becomes Sponsor of Open Source Initiative

Posted Sep 29, 2017 22:56 UTC (Fri) by evad (guest, #60553) [Link] (1 responses)

Did you see the picture in the article I linked to? SQL server uses native Windows calls on... Windows... and Linux.

Please stop pretending its a simple Linux application.

Microsoft Becomes Sponsor of Open Source Initiative

Posted Sep 30, 2017 3:25 UTC (Sat) by Cyberax (✭ supporter ✭, #52523) [Link]

Nope, SQL Server on Windows also uses Drawbridge.

Drawbridge is _not_ a subset Win32 API, it's definitely heavily influenced by Win32 but it's not just a thin wrapper. So yep, SQL Server is a second class application on Windows according to you.

And it's not like Drawbridge is something unique. Linux has Graphene ( https://github.com/oscarlab/graphene ) and WebABI and others built on the same principle.

Seriously, just download the preview version of SQL server and see for yourself.

Microsoft Becomes Sponsor of Open Source Initiative

Posted Sep 28, 2017 19:27 UTC (Thu) by evad (guest, #60553) [Link] (1 responses)

And yes, it is incorrect to say that Microsoft optimised Windows for KVM/XEN. All they did was provide information for the KVM/XEN developers to work better with Windows.

Perhaps you should not tell others off for spreading FUD when you are in fact... spreading FUD.

Microsoft Becomes Sponsor of Open Source Initiative

Posted Sep 28, 2017 19:59 UTC (Thu) by Cyberax (✭ supporter ✭, #52523) [Link]

Xen has nothing internally to do with emulating "Hyper-V protocol" or anything like it. Ditto for KVM.

The current PV drivers for Windows are developed by Citrix and they use the same protocol as Linux drivers. Not surprising, since they are talking to the same backend.

Windows did some work quietly to make sure that it's not hitting performance bottlenecks in Xen and KVM.