|By Hovhannes Avoyan||
|December 19, 2012 10:27 PM EST||
In our previous article we discussed the hardware supported features of some of the high-end network adapters. Let’s take a look how you can use some of those settings to their best advantage. Remember that the correct settings depend on the network adapter, your workload, the resources of the host computer, and of course your performance goals.
Turning on network adapter offload features typically will benefit performance.However, sometimes the network adapter might not be powerful enough to handle the offload capabilities with high throughput. For example, enabling segmentation offload can reduce the maximum sustainable throughput on some network adapters because of limited hardware resources. However, if the reduced throughput is not expected to be a limitation, you should enable offload capabilities, even for those network adapters. Some network adapters require offload features to be independently enabled for send and receive paths.
RSS can improve web scalability and performance if you have fewer network adapters than logical processors in your server. When all the web traffic is going through the RSS-capable network adapters, incoming web requests from different connections can be simultaneously processed across different CPUs. Because of the logic in RSS and HTTP for load distribution, performance can be degraded if a non-RSS-capable network adapter accepts web traffic on a server that has one or more RSS-capable network adapters. It is recommended that you use RSS-capable network adapters or disable RSS from the Advanced Properties tab. To determine whether a network adapter is RSS-capable, view the RSS information on the Advanced Properties tab for the device.
RSS Profiles and RSS Queues
RSS Profiles are new in Windows Server 2012. The default profile is NUMA Static, which changes the default behavior from previous versions of Windows. We suggest reviewing the available profiles and understanding when they are beneficial. For example, you can use Task Manager to examine if your logical processors is underutilized for receive traffic, and try increasing the number of RSS queues from the default of 2 to the maximum that your network adapter supports. Changing the number of RSS queues is an option your network adapter may have as part of the driver.
For network adapters that allow manual configuration of resources, such as receive and send buffers, you should increase the allocated resources. Some network adapters set their receive buffers low to conserve allocated memory from the host. The low value results in dropped packets and decreased performance. Therefore, for receive-intensive scenarios, it is recommended to increase the receive buffer value to the maximum. If your adapter does not supports or exposes manual configuration, it most likely dynamically configures the resources, or it might be a fixed value that you can’t change.
To control interrupt moderation, some network adapters expose different interrupt moderation levels, buffer coalescing parameters (sometimes separately for send and receive buffers), or both. You should consider interrupt moderation for CPU-bound workloads, and consider the trade-off between the host CPU savings and latency versus the increased host CPU savings because of more interrupts and less latency. If the network adapter does not perform interrupt moderation, but it does expose buffer coalescing, increasing the number of coalesced buffers allows more buffers per send or receive, which improves performance.
Your network adapter has a number of options to optimize latency caused by the operating system. This latency is the time between the network driver processing an incoming packet and the sending it back, and is usually measured in microseconds. As a comparison, the transmission time for packets transmitted over long distances is usually expressed in milliseconds. This tuning will not reduce the time a packet spends in transit.
Some tuning suggestions for microsecond-sensitive networks include:
· Set the computer BIOS to High Performance, with C-states disabled. However, this is system and BIOS dependent. Some systems provide higher performance if the operating system controls power management. You can check and adjust your power management settings from the Control Panel or by using the powercfg command.
· Set the operating system power management profile to High Performance System. For this to work as expected, your system’s BIOS has to be set to enable operating system control of power management.
· Enable Static Offloads, for example, UDP Checksums, TCP Checksums, and Send Large Offload (LSO)
· Enable RSS if the traffic is multi-streamed, such as high-volume multicast receive
· Disable the Interrupt Moderation setting for network drivers that require the lowest possible latency. The tradeoff is that this can use more CPU time.
· Handle network adapter interrupts and DPCs on a core processor that shares CPU cache with the core that is being used by the program that is handling the packet. CPU affinity tuning can be used to direct a process to certain logical processors in conjunction with RSS configuration to accomplish this. Using the same core for the interrupt, DPC, and user mode thread exhibits worse performance as load increases because the ISR, DPC, and thread contend for the use of the core.
Many hardware systems use System Management Interrupts (SMI) for a variety of maintenance functions, including reporting of ECC memory errors, legacy USB compatibility, fan control, and BIOS controlled power management. The SMI is the highest priority interrupt on the system and places the CPU in a management mode, which preempts all other activity while it runs an interrupt service routine, typically contained in BIOS.
This behavior can result in latency spikes of 100 microseconds or more. If you need to achieve the lowest latency, look for a BIOS version from your hardware provider that reduces SMIs to the lowest degree possible, referred to as “low latency BIOS” or “SMI free BIOS.” It is not possible to eliminate SMI activity altogether because it is used to control some essential functions, such as fan control.
TCP Receive Window Auto-Tuning
Prior to Windows Server 2008, the network stack used a fixed-size receive-side window that limited the overall potential throughput for connections. One of the most significant changes to the TCP stack is TCP receive window auto-tuning. You can calculate the total throughput of a single connection when you use this fixed size default as:
Total achievable throughput in bytes = TCP window * (1 / connection latency)
As an example, the achievable throughput is only 51 Mbps on a 1 GB connection with 10ms latency. With auto-tuning, the receive-side window is adjustable, and it can grow to meet the demands of the sender. It is possible for a connection to achieve a full line rate of a 1 GB connection. Network usage requirements that might have been limited in the past by the total achievable throughput of TCP connections can now fully use the network.
Windows Filtering Platform
The Windows Filtering Platform (WFP) that was introduced in Windows Vista and Windows Server 2008 provides APIs to non-Microsoft independent software vendors (ISVs) to create packet processing filters. Examples include firewall and antivirus software. Be careful that a poorly written WFP filter can significantly decrease networking performance.
The following registry keywords from Windows Server 2003 are no longer supported, and they are ignored in Windows Server 2012, as well as Windows Server 2008 R2, and Windows Server 2008:
· TcpWindowSize – HKLM\System\CurrentControlSet\Services\Tcpip\Parameters
· NumTcbTablePartitions – HKLM\system\CurrentControlSet\Services\Tcpip\Parameters
· MaxHashTableSize – HKLM\system\CurrentControlSet\Services\Tcpip\Parameters
This section lists the counters that are relevant to managing network performance.
· IPv4, IPv6
- Datagrams Received/sec
- Datagrams Sent/sec
· TCPv4, TCPv6
- Segments Received/sec
- Segments Sent/sec
- Segments Retransmitted/sec
· Network Interface(*), Network Adapter(*)
- Bytes Received/sec
- Bytes Sent/sec
- Packets Received/sec
- Packets Sent/sec
- Output Queue Length
This counter is the length of the output packet queue (in packets). If this is longer than 2, delays occur. You should find the bottleneck and eliminate it if you can. Because NDIS queues the requests, this length should always be 0.
· Processor Information
- % Processor Time
- DPCs Queued/sec
This counter is an average rate at which DPCs were added to the logical processor’s DPC queue. Each logical processor has its own DPC queue. This counter measures the rate at which DPCs are added to the queue, not the number of DPCs in the queue. It displays the difference between the values that were observed in the last two samples, divided by the duration of the sample interval.
Potential Network Problems
· Network Interface(*), Network Adapter(*)
- Packets Received Discarded
- Packets Received Errors
- Packets Outbound Discarded
- Packets Outbound Errors
· WFPv4, WFPv6
- Packets Discarded/sec
· UDPv4, UDPv6
- Datagrams Received Errors
· TCPv4, TCPv6
- Connection Failures
- Connections Reset
· Network QoS Policy
- Packets dropped
- Packets dropped/sec
· Per Processor Network Interface Card Activity
- Low Resource Receive Indications/sec
- Low Resource Received Packets/sec
· Microsoft Winsock BSP
- Dropped Datagrams
- Dropped Datagrams/sec
- Rejected Connections
- Rejected Connections/sec
Receive Side Coalescing (RSC) performance
· Network Adapter(*)
- TCP Active RSC Connections
- TCP RSC Average Packet Size
- TCP RSC Coalesced Packets/sec
- TCP RSC Exceptions/sec
WebRTC is about the data channel as much as about video and audio conferencing. However, basically all commercial WebRTC applications have been built with a focus on audio and video. The handling of “data” has been limited to text chat and file download – all other data sharing seems to end with screensharing. What is holding back a more intensive use of peer-to-peer data? In her session at @ThingsExpo, Dr Silvia Pfeiffer, WebRTC Applications Team Lead at National ICT Australia, will look at different existing uses of peer-to-peer data sharing and how it can become useful in a live session to...
Oct. 8, 2015 12:00 PM EDT Reads: 597
As a company adopts a DevOps approach to software development, what are key things that both the Dev and Ops side of the business must keep in mind to ensure effective continuous delivery? In his session at DevOps Summit, Mark Hydar, Head of DevOps, Ericsson TV Platforms, will share best practices and provide helpful tips for Ops teams to adopt an open line of communication with the development side of the house to ensure success between the two sides.
Oct. 8, 2015 12:00 PM EDT Reads: 569
NHK, Japan Broadcasting, will feature the upcoming @ThingsExpo Silicon Valley in a special 'Internet of Things' and smart technology documentary that will be filmed on the expo floor between November 3 to 5, 2015, in Santa Clara. NHK is the sole public TV network in Japan equivalent to the BBC in the UK and the largest in Asia with many award-winning science and technology programs. Japanese TV is producing a documentary about IoT and Smart technology and will be covering @ThingsExpo Silicon Valley. The program, to be aired during the peak viewership season of the year, will have a major impac...
Oct. 8, 2015 12:00 PM EDT Reads: 248
There are so many tools and techniques for data analytics that even for a data scientist the choices, possible systems, and even the types of data can be daunting. In his session at @ThingsExpo, Chris Harrold, Global CTO for Big Data Solutions for EMC Corporation, will show how to perform a simple, but meaningful analysis of social sentiment data using freely available tools that take only minutes to download and install. Participants will get the download information, scripts, and complete end-to-end walkthrough of the analysis from start to finish. Participants will also be given the pract...
Oct. 8, 2015 11:45 AM EDT Reads: 199
SYS-CON Events announced today that IBM Cloud Data Services has been named “Bronze Sponsor” of SYS-CON's 17th Cloud Expo, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. IBM Cloud Data Services offers a portfolio of integrated, best-of-breed cloud data services for developers focused on mobile computing and analytics use cases.
Oct. 8, 2015 11:00 AM EDT Reads: 723
The enterprise is being consumerized, and the consumer is being enterprised. Moore's Law does not matter anymore, the future belongs to business virtualization powered by invisible service architecture, powered by hyperscale and hyperconvergence, and facilitated by vertical streaming and horizontal scaling and consolidation. Both buyers and sellers want instant results, and from paperwork to paperless to mindless is the ultimate goal for any seamless transaction. The sweetest sweet spot in innovation is automation. The most painful pain point for any business is the mismatch between supplies a...
Oct. 8, 2015 10:30 AM EDT Reads: 175
The buzz continues for cloud, data analytics and the Internet of Things (IoT) and their collective impact across all industries. But a new conversation is emerging - how do companies use industry disruption and technology enablers to lead in markets undergoing change, uncertainty and ambiguity? Organizations of all sizes need to evolve and transform, often under massive pressure, as industry lines blur and merge and traditional business models are assaulted and turned upside down. In this new data-driven world, marketplaces reign supreme while interoperability, APIs and applications deliver un...
Oct. 8, 2015 10:30 AM EDT Reads: 199
The Internet of Things (IoT) is growing rapidly by extending current technologies, products and networks. By 2020, Cisco estimates there will be 50 billion connected devices. Gartner has forecast revenues of over $300 billion, just to IoT suppliers. Now is the time to figure out how you’ll make money – not just create innovative products. With hundreds of new products and companies jumping into the IoT fray every month, there’s no shortage of innovation. Despite this, McKinsey/VisionMobile data shows "less than 10 percent of IoT developers are making enough to support a reasonably sized team....
Oct. 8, 2015 10:30 AM EDT
"Matrix is an ambitious open standard and implementation that's set up to break down the fragmentation problems that exist in IP messaging and VoIP communication," explained John Woolf, Technical Evangelist at Matrix, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Oct. 8, 2015 07:00 AM EDT Reads: 5,863
WebRTC has had a real tough three or four years, and so have those working with it. Only a few short years ago, the development world were excited about WebRTC and proclaiming how awesome it was. You might have played with the technology a couple of years ago, only to find the extra infrastructure requirements were painful to implement and poorly documented. This probably left a bitter taste in your mouth, especially when things went wrong.
Oct. 8, 2015 06:00 AM EDT Reads: 756
Nowadays, a large number of sensors and devices are connected to the network. Leading-edge IoT technologies integrate various types of sensor data to create a new value for several business decision scenarios. The transparent cloud is a model of a new IoT emergence service platform. Many service providers store and access various types of sensor data in order to create and find out new business values by integrating such data.
Oct. 8, 2015 04:00 AM EDT Reads: 540
The broad selection of hardware, the rapid evolution of operating systems and the time-to-market for mobile apps has been so rapid that new challenges for developers and engineers arise every day. Security, testing, hosting, and other metrics have to be considered through the process. In his session at Big Data Expo, Walter Maguire, Chief Field Technologist, HP Big Data Group, at Hewlett-Packard, will discuss the challenges faced by developers and a composite Big Data applications builder, focusing on how to help solve the problems that developers are continuously battling.
Oct. 8, 2015 04:00 AM EDT Reads: 483
WebRTC converts the entire network into a ubiquitous communications cloud thereby connecting anytime, anywhere through any point. In his session at WebRTC Summit,, Mark Castleman, EIR at Bell Labs and Head of Future X Labs, will discuss how the transformational nature of communications is achieved through the democratizing force of WebRTC. WebRTC is doing for voice what HTML did for web content.
Oct. 8, 2015 03:00 AM EDT Reads: 1,372
Who are you? How do you introduce yourself? Do you use a name, or do you greet a friend by the last four digits of his social security number? Assuming you don’t, why are we content to associate our identity with 10 random digits assigned by our phone company? Identity is an issue that affects everyone, but as individuals we don’t spend a lot of time thinking about it. In his session at @ThingsExpo, Ben Klang, Founder & President of Mojo Lingo, will discuss the impact of technology on identity. Should we federate, or not? How should identity be secured? Who owns the identity? How is identity ...
Oct. 8, 2015 03:00 AM EDT Reads: 433
Developing software for the Internet of Things (IoT) comes with its own set of challenges. Security, privacy, and unified standards are a few key issues. In addition, each IoT product is comprised of at least three separate application components: the software embedded in the device, the backend big-data service, and the mobile application for the end user's controls. Each component is developed by a different team, using different technologies and practices, and deployed to a different stack/target - this makes the integration of these separate pipelines and the coordination of software upd...
Oct. 8, 2015 03:00 AM EDT Reads: 279
WebRTC services have already permeated corporate communications in the form of videoconferencing solutions. However, WebRTC has the potential of going beyond and catalyzing a new class of services providing more than calls with capabilities such as mass-scale real-time media broadcasting, enriched and augmented video, person-to-machine and machine-to-machine communications. In his session at @ThingsExpo, Luis Lopez, CEO of Kurento, will introduce the technologies required for implementing these ideas and some early experiments performed in the Kurento open source software community in areas ...
Oct. 8, 2015 02:00 AM EDT Reads: 687
WebRTC: together these advances have created a perfect storm of technologies that are disrupting and transforming classic communications models and ecosystems. In his session at WebRTC Summit, Cary Bran, VP of Innovation and New Ventures at Plantronics and PLT Labs, will provide an overview of this technological shift, including associated business and consumer communications impacts, and opportunities it may enable, complement or entirely transform.
Oct. 8, 2015 01:30 AM EDT Reads: 732
“In the past year we've seen a lot of stabilization of WebRTC. You can now use it in production with a far greater degree of certainty. A lot of the real developments in the past year have been in things like the data channel, which will enable a whole new type of application," explained Peter Dunkley, Technical Director at Acision, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Oct. 8, 2015 12:00 AM EDT Reads: 6,951
SYS-CON Events announced today that Luxoft Holding, Inc., a leading provider of software development services and innovative IT solutions, has been named “Bronze Sponsor” of SYS-CON's @ThingsExpo, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Luxoft’s software development services consist of core and mission-critical custom software development and support, product engineering and testing, and technology consulting.
Oct. 7, 2015 09:15 PM EDT Reads: 643
SYS-CON Events announced today that Dyn, the worldwide leader in Internet Performance, will exhibit at SYS-CON's 17th International Cloud Expo®, which will take place on November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Dyn is a cloud-based Internet Performance company. Dyn helps companies monitor, control, and optimize online infrastructure for an exceptional end-user experience. Through a world-class network and unrivaled, objective intelligence into Internet conditions, Dyn ensures traffic gets delivered faster, safer, and more reliably than ever.
Oct. 7, 2015 09:00 PM EDT Reads: 532