NVIDIA GRID: Citrix HDX adds support for Relative and Absolute Mouse Modes to Linux Receiver

Update: 14th September 2016 – Receiver For Windows 4.5 released today now adds support for Windows in addition to Linux!

Just a quick blog to highlight the availability on the Citrix HDX/ICA protocol of a feature enabling Relative Mouse mode. This is a particularly interesting for many NVIDIA GRID vGPU and graphical users as it enables better behavior of certain gaming like applications, particularly those favoured in federal simulations (battle and flight-simulators) e.g Bohemia Simulations VBS 2 & 3. Before on certain application without using an addition gamepad device the mouse could behave strangely ending up with the user pointing their barrel at the ground or sky. Continue reading NVIDIA GRID: Citrix HDX adds support for Relative and Absolute Mouse Modes to Linux Receiver

When to start your tweets with a “@”! Why some people add a dot e.g. “.@rhbbse” to tweets

dottweet.pngThe quirk of twitter

To avoid personal chatter spreading and swamping others twitter put in a clever yet obscure feature to ensure those tweets you want to broadcast spread and one-on-one chatter dies a quick death in the twitterverse.

If you send a tweet starting with a handle i.e. an @ is the first character:

  • “@rhbbse you are awesome”

It will get seen in news streams by me and anyone who follows BOTH of us, “mutual friends”

If you want the world to know though you have to avoid the @ e.g.

By adding a “.” in front or some other text e.g. “Hey world” the tweet will go to all your followers and not just those that we share.

This also applies when retweeting others’ tweets which is why you often see a “.” added.


You can read more about this quirk here:


Significant leaps in virtualized NVIDIA vGPU monitoring

Read the documentation – the User Guide provided alongside the managmeent SDK is really comprehensive!

Today NVIDIA announced a new monitoring SDK / API incorporated into its GRID vGPU products as part of their GRID August 2016 (4.0) release. This will be available from Friday 26th August 2016 as a software release for existing hardware, greatly enhancing the functionality for existing as well as new customers. (You can read the announcement here).

NVIDIA has broken ranks with traditional hardware-only GPU models and recognized enterprises needs software to manage and monitor GPUs as a component of the data centre. Software licensing has enabled existing customers to benefit from new features with fully supported software, directly supported by NVIDIA (you wouldn’t run your Microsoft OS or CAD software unsupported!). Continue reading Significant leaps in virtualized NVIDIA vGPU monitoring

“Now, you don’t punish anyone, Dutch or otherwise, for having big boobs.” – Women in IT

I couldn’t really think of an image I wanted to use for this blog – so here’s a pretty picture of Bury St. Edmunds where it appears there are some women employed in IT!

“Now, you don’t punish anyone, Dutch or otherwise, for having big boobs.” is a famous quote from the UK Comedy “The Office”. In the UK this week there has been a “can sexy women work in IT” story in the news this week. Amazingly focused on a woman working in IT in my rural home town Bury St. Edmunds (which was one of the most surprising elements to the story – I thought I was the “only woman in IT in the village”!. The Office sketch is 15 year old and pre-dates the explosion in social media networking, the comical figure of David Brent discussing women’s bust size in the workplace actually seems to have come true. Continue reading “Now, you don’t punish anyone, Dutch or otherwise, for having big boobs.” – Women in IT

Optimising TCP for Citrix HDX/ICA including Netscaler

Marius Sandbu – NGCA (NVIDIA GRID Community Advisor)  aka Clever Viking!

The TCP implementation within Citrix HDX/ICA protocol used by XenDesktop and XenApp and also Citrix Netscaler is pretty Vanilla to the original TCP/IP standards and definition and the out-of-the-box configuration usually does a good job on LAN. However, for WAN scenarios particularly with higher latencies and certain kinds of data (file transfers), Citrix deployments can benefit greatly from some tuning.


One of our new NGCAs (NVIDIA GRID Community Advisors) Marius Sandbu has written a must-read blog on how to optimize TCP with a Citrix Netscaler in the equation: http://msandbu.org/tag/netscaler-tcp-profile/Marius highlights some of the configuration optimisations hidden away in the Netscaler documentation and you’ll probably want to refer to that  documentation too (https://docs.citrix.com/en-us/netscaler/11-1/system/TCP_Congestion_Control_and_Optimization_General.html).

Citrix HDX TCP is not optimized for many WAN scenarios but at the moment it can also be tuned manually following this advice: CTX125027 – How to Optimize HDX Bandwidth Over High Latency Connections. This is one configuration I’d love to see Citrix automate as having to tune and configure the receiver is fiddly and also not possible in organisations/scenarios where the end-points and server/network infrastructure might be provided by different teams or even companies (e.g. IaaS).


For Citrix NVIDIA GRID vGPU customers with looking at high network latency scenarios – it really is worth investigating the potential and benefits of TCP window tuning. I’d be really interested to hear feedback if you have tried this and what your experience / thoughts are too!


Norwegian, Marius Sandbu was recently awarded NGCA status by NVIDIA for his work with our community through his Netscaler, remoting protocols and experience with technologies such as UDP and TCP/IP. You can follow him on twitter @msandbu and of course do follow his excellent blog on http://msandbu.org/ !!!

NVIDIA GRID – A Guide on GPU Metric Integration for Citrix XenServer

Just a quick blog aimed at those looking to develop GPU hypervisor monitoring products by integrating the NVIDIA GPU metrics exposed by XenServer via their APIs. Really it’s a bit of a guide as to where to find the information provided by Citrix.



Two NVIDIA GPU technologies are available on Citrix XenServer:

  • GPU (PCIe) pass-through (including GPU-sharing for XenApp and VDI passthrough)
  • vGPU (shared GPU technologies)

Owing to the nature of PCIe passthrough whereby the hypervisor is bypassed and the VM itself obtains complete control and sole access to the GPU, host and hypervisor level metrics are not available to the NVIDIA SDK and APIs on host nor to the hypervisor.

Developing a supported solution

Many Citrix customers insist on a monitoring solution being certified by the vendor via the Citrix Ready program. ISVs are advised to join the Citrix Ready program (access level is free) to obtain advise on developing a supported product and to eventually certify and market their product. In particular ISVs are recommended to evaluate the conditions of the vendor self-certification “kit” for supported products.

Whilst monitoring can be performed by inserting a kernel module or supplemental pack into XenServer’s dom0 this is an unsupported mechanism that Citrix generally will not support and customers are rarely willing to compromise their support agreements to use such products. ISVs are strongly advised to consider using the XenServer APIs and SDK to access metrics in a supported manner. See: https://www.citrix.com/partner-programs/citrix-ready/test.html (under XenServer-> Citrix XenServer (6.x) Integrated ISV Self-Certification Kit).

XenServer SDK / API

The XenServer API provides bindings for five languages: C, C#, Java, Python and Powershell.

XenServer maintains a landing page for ISV developers: http://xenserver.org/partners/developing-products-for-xenserver.html

Additionally there is developer (SDK) support forum where many XenServer staff answer questions: http://discussions.citrix.com/forum/1276-xenserver-sdk/

XenServer Metrics

XenServer captures metrics in RRDs. Details of the RRDs, code examples and information on how the XenServer SDK can be used to access the metrics are given on this landing page: http://xenserver.org/partners/developing-products-for-xenserver/18-sdk-development/96-xs-dev-rrds.html

XenServer have integrated many of the metrics available from NVIDIAs NVML interface into their RRDs. This means customers can access the metrics via the XenServer APIs in a supported manner rather than inserting unsupported kernel modules to call NVML in the hypervisor’s host operating system (dom0).  See https://www.citrix.com/blogs/2014/01/22/xenserverxendesktop-vgpu-new-metrics-available-to-monitor-nvidia-grid-gpus/

XenServer APIs – querying GPU infrastructure:

For information on which VMs have vGPUs, the type of vGPU profile etc. see http://nvidia.custhelp.com/app/answers/detail/a_id/4117/kw/citrix%20monitoring under “Checking your GPU configuration” for links to appropriate XenServer documentation.


Useful links:


NVIDIA – significant increases in parental benefits for employees

Rachel & Jonny

Yesterday all of us who work for NVIDIA got an email from our flamboyant CEO Jensen Huang. With some really quite startling positive changes to employee benefits for maternity and parental leave affecting employees worldwide. Including worldwide policy of 22 weeks full pay for maternity leave, which far out-strips statutory and industry standards in the majority of countries. Whilst many countries like the UK offer statutory maternity pay for longer in the UK and elsewhere the majority of the time is capped at a rate of under £150 a week.

The Announcement

“Building a great company is all about our people – attracting great people, and creating a culture that supports us in doing our life’s work and building our lives.

One of the best things we do is our parental leave benefit.  Today, I’m delighted to announce that we’ve worked through all the international logistics so that we can extend this benefit to all NVIDIANs around the world.  

Birth mothers will receive 22 weeks of fully paid leave. Fathers, adoptive and foster parents will get 12 weeks fully paid. And new parents can take a further eight weeks of flex time, to help with the transition back to work. In countries where the law provides for additional benefits, local employees are eligible for those too. This benefit is also available to parents who have recently welcomed a child. If you’re not able to take time off, a bonus payment may be available.

This benefit is not just about the time off.  It’s mostly about our colleagues picking up the slack to support us during this time.  It gives us all great joy to support our families during one of the happiest moments in our lives, and at a time when we need the support most. 

Keep up the great work everyone.  We are building one of the world’s great companies, one that generations of NVIDIAN’s will be proud of.   


Why is this news?

  • This is significantly better than NVIDIA have to legally provide anywhere
  • It applies to employees worldwide – I’ve worked for companies where companies treat employees differently according to local minimum legislation and it can foster resentment. If something is the right thing to do – then just do it!
  • It’s not just maternity but also parental leave that have been enhanced for all employees. This is a really important factor (in my opinion) in ensuring women of child care age are not seen as a liability or potentially – when the guys in the office take time too
  • This will make it even easier to attract and retain staff, which frankly makes everyone’s lives easier
  • Whilst some (mainly European) countries offer fantastic parental packages this is usually state funded at the costs of high taxes. E.g. Sweden. This is being driven by NVIDIA, presumably at large costs, a private USA company. In the USA only 11% of employers offer any maternity leave let alone anything of practical financial benefit (see http://www.theatlantic.com/business/archive/2014/06/good-job-america-a-map-of-maternity-leave-policies-around-the-world/373117/)

What does this mean for NVIDIA customers?

It was an internal memo, most customers I doubt will be aware but long-term feeling the vibe internally I think it will reap subtle benefits for customers:

  • Consistent enterprise staffing – an organization acknowledging smooth businesses run around accommodating real people
  • Better staffing – NVIDIA already has a reputation for paying to attract the best, right down to interns (see here). This just makes it even easier to attract those who have the talent and experience to be choosy.
  • That support or sales guy or girl who picks up the phone may well be a little perkier and responsive because they have the ability to take time when their baby hasn’t slept for three months, they aren’t distracted because they’ve left their teeny 6 week old baby in nursery to pay the mortgage etc…
  • Choosing an ethical supplier is becoming more important to many, recognizing that it’s a choice – why choose a company with dubious employment practices when you you can pick one that treats its staff well and also equally regardless of whether they live in a rich country, second or third-world one.

I’d like to think this would encourage others in the IT industry to raise their game, I’m skeptical it will as at least in the UK there has been a trend for companies to normalize to statutory minimum forming a pseudo-cartel. This announcement went against the trend putting such benefits back on the agenda in IT.

Recently the Maersk group offered a worldwide similar package (see here), but that was newsworthy and from a Scandinavian corporation. The Maersk group announcement contained some startling business justification including this quote:

  • “Women leaving the workforce in connection to childbirth is a global problem, and based on previous analysis conducted by consultancy KPMG, it costs global businesses $47 billion every year* to recruit and train new employees to replace women who do not stay in the workforce after maternity leave.”


I can’t comment on NVIDIA’s actual motives, rational or messaging on this just how it’s gone down with low-level employees like me who were just surprised and delighted this decision was made. It’s not considered good form to discuss company memos or benefits but in this case I felt the need to raise this discussion wider than NVIDIA and would be interesting to hear others thoughts/experiences.