RoCE Fails to Scale – the Dangers of Sliding Down the RoCE Path

November 30, 2015

A recent paper published by a public cloud vendor and others reveals the trials and tribulations of their RoCE experience, and the scale of their deployment woes1.

The authors, including the RoCE vendor and some of the staunchest of RoCE proponents, reveal the severity of the problems faced, with “poor application performance,” “head-of-line blocking,” “unfairness,” “congestion that spreads” in the network, and “performance that degrades” under load.

The authors then attempt to patch together pieces from Ethernet and Data Center TCP into a sideband congestion control scheme (DCQCN). However, DCQCN remains an unsuccessful attempt to address the issues, as it continues to require the same blunt pause mechanisms that expose the network to congestion collapse.

Thus, the paper serves as a proof that the basis behind RoCE of airlifting the “incompatible InfiniBand” into the Ethernet space is doomed to fail, due to missing critical stability mechanisms.

Heeding the warnings from this paper and other known experiences, users are avoiding scalability limitations and dangerous network meltdowns by staying clear of RoCE. Instead, many are selecting the iWARP RDMA over Ethernet standard. iWARP is a scalable, easy to use, plug-and-play protocol, which leverages a proven and mature TCP/IP foundation, and originates from the fully open IETF standards process. There is no reason to slide down the RoCE path, when a stable, robust, cloud ready alternative is available and provides competitive performance and benefits.

And so, in light of mounting evidence that users of RoCE are facing major deployment problems, the truth is finally emerging and exposing the misleading claims by the aggressive FUD campaign accompanying the push for InfiniBand over Ethernet.

The previously mentioned paper discussed the widespread congestion failures observed when RoCE is deployed at scale, as reported by Microsoft Azure, widely advertised as the main datacenter proof point for RoCE. The paper also discussed the DCQCN scheme put together to plug some of the gaping holes in InfiniBand’s Ethernet incursion 1.

The perils of using PFC in a large-scale deployment are well known. The need for PFC alone should prevent one’s slide down the RoCE path. Unfortunately, the repetition of baseless marketing fluff and technically meaningless statements such as “due to end-to-end loss recovery, iWarp [sic] cannot offer ultra-low latency like RoCEv2” and the shallowness of their understanding of iWARP, put into question the objectiveness of their analysis and conclusions.

Nevertheless, there is no hiding the fact that the RoCE problems are real, and the successively attempted solutions haphazard and incomplete, with RoCE users repeatedly having to undergo emergency protocol surgery. These hard learnt lessons are helping others avoid the same mistake by selecting iWARP, and across the board, a sea change is in effect as the industry reels back from the edge of a RoCE abyss.

Note: This Center Stage article is an excerpt of a Chelsio white paper, RoCE Fails to Scale: Repetitive Protocol Surgery or the Dangers of Sliding Down the RoCE Path.  You can download a copy at http://www.chelsio.com/wp-content/uploads/resources/RoCE-Deployment-Challenges-for-Clouds.pdf

1 Yibo Zhu et al., SIGCOMM 2015, Congestion Control for Large-Scale RDMA Deployments, http://www.cs.ucsb.edu/~yibo/

 

Subscribe to HPCwire's Weekly Update!

Be the most informed person in the room! Stay ahead of the tech trends with industy updates delivered to you every week!

LLNL Leverages Supercomputing to Identify COVID-19 Antibody Candidates

March 30, 2020

As COVID-19 sweeps the globe to devastating effect, supercomputers around the world are spinning up to fight back by working on diagnosis, epidemiology, treatment and vaccine development. Now, Lawrence Livermore National Read more…

By Staff report

Weather at Exascale: Load Balancing for Heterogeneous Systems

March 30, 2020

The first months of 2020 were dominated by weather and climate supercomputing news, with major announcements coming from the UK, the European Centre for Medium-Range Weather Forecasts and the U.S. National Oceanic and At Read more…

By Oliver Peckham

Q&A Part Two: ORNL’s Pooser on Progress in Quantum Communication

March 30, 2020

Quantum computing seems to get more than its fair share of attention compared to quantum communication. That’s despite the fact that quantum networking may be nearer to becoming a practical reality. In this second inst Read more…

By John Russell

SiFive Accelerates Chip Design with Cloud Tools

March 25, 2020

Chip designers are drawing on new cloud resources along with conventional electronic design automation (EDA) tools to accelerate IC templates from tape-out to custom silicon. Among the challengers to chip design leade Read more…

By George Leopold

What’s New in Computing vs. COVID-19: White House Initiative, Frontera, RIKEN & More

March 25, 2020

Supercomputing, big data and artificial intelligence are crucial tools in the fight against the coronavirus pandemic. Around the world, researchers, corporations and governments are urgently devoting their computing reso Read more…

By Oliver Peckham

AWS Solution Channel

Amazon FSx for Lustre Update: Persistent Storage for Long-Term, High-Performance Workloads

Last year I wrote about Amazon FSx for Lustre and told you how our customers can use it to create pebibyte-scale, highly parallel POSIX-compliant file systems that serve thousands of simultaneous clients driving millions of IOPS (Input/Output Operations per Second) with sub-millisecond latency. Read more…

DoE Expands on Role of COVID-19 Supercomputing Consortium

March 25, 2020

After announcing the launch of the COVID-19 High Performance Computing Consortium on Sunday, the Department of Energy yesterday provided more details on its scope and operation in a briefing led by Undersecretary of Ener Read more…

By John Russell

Weather at Exascale: Load Balancing for Heterogeneous Systems

March 30, 2020

The first months of 2020 were dominated by weather and climate supercomputing news, with major announcements coming from the UK, the European Centre for Medium- Read more…

By Oliver Peckham

Q&A Part Two: ORNL’s Pooser on Progress in Quantum Communication

March 30, 2020

Quantum computing seems to get more than its fair share of attention compared to quantum communication. That’s despite the fact that quantum networking may be Read more…

By John Russell

DoE Expands on Role of COVID-19 Supercomputing Consortium

March 25, 2020

After announcing the launch of the COVID-19 High Performance Computing Consortium on Sunday, the Department of Energy yesterday provided more details on its sco Read more…

By John Russell

[email protected] Rallies a Legion of Computers Against the Coronavirus

March 24, 2020

Last week, we highlighted [email protected], a massive, crowdsourced computer network that has turned its resources against the coronavirus pandemic sweeping the globe – but [email protected] isn’t the only game in town. The internet is buzzing with crowdsourced computing... Read more…

By Oliver Peckham

Conversation: ANL’s Rick Stevens on DoE’s AI for Science Project

March 23, 2020

With release of the Department of Energy’s AI for Science report in late February, the effort to build a national AI program, modeled loosely on the U.S. Exascale Initiative, enters a new phase. Project leaders have already had early discussions with Congress... Read more…

By John Russell

Servers Headed to Junkyard Find 2nd Life Fighting Cancer in Clusters

March 20, 2020

Ottawa-based charitable organization Cancer Computer is on a mission to stamp out cancer and other life-threatening diseases, including coronavirus, by putting Read more…

By Tiffany Trader

Kubernetes and HPC Applications in Hybrid Cloud Environments – Part II

March 19, 2020

With the rise of cloud services, CIOs are recognizing that applications, middleware, and infrastructure running in various compute environments need a common management and operating model. Maintaining different application and middleware stacks on-premises and in cloud environments, by possibly using different specialized infrastructure and application... Read more…

By Daniel Gruber,Burak Yenier and Wolfgang Gentzsch, UberCloud

Intel’s Neuromorphic Chip Scales Up (and It Smells)

March 18, 2020

Neuromorphic chips attempt to directly mimic the behavior of the human brain. Intel, which introduced its Loihi neuromorphic chip in 2017, has just announced that Loihi has been scaled up into a system that simulates over 100 million neurons. Furthermore, it announced that the chip smells. Read more…

By Oliver Peckham

[email protected] Turns Its Massive Crowdsourced Computer Network Against COVID-19

March 16, 2020

For gamers, fighting against a global crisis is usually pure fantasy – but now, it’s looking more like a reality. As supercomputers around the world spin up Read more…

By Oliver Peckham

Julia Programming’s Dramatic Rise in HPC and Elsewhere

January 14, 2020

Back in 2012 a paper by four computer scientists including Alan Edelman of MIT introduced Julia, A Fast Dynamic Language for Technical Computing. At the time, t Read more…

By John Russell

Global Supercomputing Is Mobilizing Against COVID-19

March 12, 2020

Tech has been taking some heavy losses from the coronavirus pandemic. Global supply chains have been disrupted, virtually every major tech conference taking place over the next few months has been canceled... Read more…

By Oliver Peckham

[email protected] Rallies a Legion of Computers Against the Coronavirus

March 24, 2020

Last week, we highlighted [email protected], a massive, crowdsourced computer network that has turned its resources against the coronavirus pandemic sweeping the globe – but Folding[email protected] isn’t the only game in town. The internet is buzzing with crowdsourced computing... Read more…

By Oliver Peckham

Steve Scott Lays Out HPE-Cray Blended Product Roadmap

March 11, 2020

Last week, the day before the El Capitan processor disclosures were made at HPE's new headquarters in San Jose, Steve Scott (CTO for HPC & AI at HPE, and former Cray CTO) was on-hand at the Rice Oil & Gas HPC conference in Houston. He was there to discuss the HPE-Cray transition and blended roadmap, as well as his favorite topic, Cray's eighth-gen networking technology, Slingshot. Read more…

By Tiffany Trader

DoE Expands on Role of COVID-19 Supercomputing Consortium

March 25, 2020

After announcing the launch of the COVID-19 High Performance Computing Consortium on Sunday, the Department of Energy yesterday provided more details on its sco Read more…

By John Russell

Fujitsu A64FX Supercomputer to Be Deployed at Nagoya University This Summer

February 3, 2020

Japanese tech giant Fujitsu announced today that it will supply Nagoya University Information Technology Center with the first commercial supercomputer powered Read more…

By Tiffany Trader

Tech Conferences Are Being Canceled Due to Coronavirus

March 3, 2020

Several conferences scheduled to take place in the coming weeks, including Nvidia’s GPU Technology Conference (GTC) and the Strata Data + AI conference, have Read more…

By Alex Woodie

Leading Solution Providers

SC 2019 Virtual Booth Video Tour

AMD
AMD
ASROCK RACK
ASROCK RACK
AWS
AWS
CEJN
CJEN
CRAY
CRAY
DDN
DDN
DELL EMC
DELL EMC
IBM
IBM
MELLANOX
MELLANOX
ONE STOP SYSTEMS
ONE STOP SYSTEMS
PANASAS
PANASAS
SIX NINES IT
SIX NINES IT
VERNE GLOBAL
VERNE GLOBAL
WEKAIO
WEKAIO

Cray to Provide NOAA with Two AMD-Powered Supercomputers

February 24, 2020

The United States’ National Oceanic and Atmospheric Administration (NOAA) last week announced plans for a major refresh of its operational weather forecasting supercomputers, part of a 10-year, $505.2 million program, which will secure two HPE-Cray systems for NOAA’s National Weather Service to be fielded later this year and put into production in early 2022. Read more…

By Tiffany Trader

Exascale Watch: El Capitan Will Use AMD CPUs & GPUs to Reach 2 Exaflops

March 4, 2020

HPE and its collaborators reported today that El Capitan, the forthcoming exascale supercomputer to be sited at Lawrence Livermore National Laboratory and serve Read more…

By John Russell

Summit Supercomputer is Already Making its Mark on Science

September 20, 2018

Summit, now the fastest supercomputer in the world, is quickly making its mark in science – five of the six finalists just announced for the prestigious 2018 Read more…

By John Russell

IBM Unveils Latest Achievements in AI Hardware

December 13, 2019

“The increased capabilities of contemporary AI models provide unprecedented recognition accuracy, but often at the expense of larger computational and energet Read more…

By Oliver Peckham

IBM Debuts IC922 Power Server for AI Inferencing and Data Management

January 28, 2020

IBM today launched a Power9-based inference server – the IC922 – that features up to six Nvidia T4 GPUs, PCIe Gen 4 and OpenCAPI connectivity, and can accom Read more…

By John Russell

TACC Supercomputers Run Simulations Illuminating COVID-19, DNA Replication

March 19, 2020

As supercomputers around the world spin up to combat the coronavirus, the Texas Advanced Computing Center (TACC) is announcing results that may help to illumina Read more…

By Staff report

University of Stuttgart Inaugurates ‘Hawk’ Supercomputer

February 20, 2020

This week, the new “Hawk” supercomputer was inaugurated in a ceremony at the High-Performance Computing Center of the University of Stuttgart (HLRS). Offici Read more…

By Staff report

Summit Joins the Fight Against the Coronavirus

March 6, 2020

With the coronavirus sweeping the globe, tech conferences and supply chains are being hit hard – but now, tech is hitting back. Oak Ridge National Laboratory Read more…

By Staff report

  • arrow
  • Click Here for More Headlines
  • arrow
Do NOT follow this link or you will be banned from the site!
Share This