ARCHER2 Weekly Newsletter

Maintenance sessions: Wednesdays 24th and 31st August

There will two partial essential maintenance sessions on ARCHER2 to allow the essential networking work to take place:

  • Wednesday 24th August 0900 - 1300 (time to be confirmed)
  • Wednesday 31st August 0900 - 1100 (time to be confirmed)

During these times, users will not be able to connect to ARCHER2 via the login nodes and will not be able to access data. The compute nodes will be operational and will continue to run jobs and new jobs will start.

Users will also be unable to connect to the SAFE during these times.

We apologise for any inconvenience caused by this essential network work and we will notify users as soon as the work has been completed and the full service is available again.

Performance of different routing protocols on ARCHER2: OpenFabrics and UCX

Wednesday date 17th August 2022 15:00 - 16:00 BST
(Postponed from 20th July)

In this presentation, we report on a comparison on performance between different routing protocols underlying the Cray MPICH library on a HPE Cray EX system for a variety of application and synthetic benchmarks. The ARCHER2 system allows users to select, at runtime, between two different underlying routing protocols: OpenFabrics (OFI) and Mellanox UCX (UCX). The CSE team have compared the performance of OFI and UCX for different applications from a variety of research areas (CASTEP, CP2K, GROMACS, NEMO, OpenSBLI, VASP) and the performance of the OSU MPI benchmarks. We find that the choice of routing protocol can have a profound effect on application performance and that the best choice is dependent on the number of nodes, the application and the benchmark case used for the performance evaluation. This makes providing general advice to users challenging. We summarise the data we have gathered so far and the advice we provide to users; and provide an overview of what future investigations we have planned.

Details and join link:

Efficient Parallel IO

David Henty EPCC
23 August 2022 09:30 - 16:30 BST

One of the greatest challenges to running parallel applications on large numbers of processors is how to handle file IO. Standard Unix IO routines are not designed with parallelism in mind, and IO overheads can grow to dominate the overall runtime. Parallel file systems are optimised for large volumes of data, but performance can be far from optimal if every process opens its own file or if all IO is funnelled through a single controller process.

This hands-on course explores a range of issues related to parallel IO. It uses ARCHER2 and its parallel Lustre file system as a platform for the exercises; however, almost all the IO concepts and performance considerations are applicable to any parallel system.

Full details and registration:

Introduction to OpenMP

Mark Bull EPCC
30th & 31st August, 6th September 2022 09:00 - 17:00 BST

This course will take place over three days on 30th and 31st August and 6th September 2022.

Almost all modern computers now have a shared-memory architecture with multiple CPUs connected to the same physical memory, for example multicore laptops or large multi-processor compute servers. This course covers OpenMP, the industry standard for shared-memory programming, which enables serial programs to be parallelised easily using compiler directives. Users of desktop machines can use OpenMP on its own to improve program performance by running on multiple cores; users of parallel supercomputers can use OpenMP in conjunction with MPI to better exploit the shared-memory capabilities of the compute nodes.

This course will cover an introduction to the fundamental concepts of the shared variables model, followed by the syntax and semantics of OpenMP and how it can be used to parallelise real programs. Hands-on practical programming exercises will be included, with access to HPC provided for the duration of the course. Prerequisites:

This course is aim at attendees with prior experience of programming in C, C++ or Fortran. Some familiarity with HPC systems is helpful but not essential. Learning outcomes:

At the end of the course, attendees should be equipped with the skills to write correct parallel programs using the core functionality of OpenMP, and understand the main issues affecting performance of shared memory parallel programs

Full details and registration:

ARCHER2 Image and Video Competition 2022

Share your images and videos to support excellence and promote the contribution of ARCHER and ARCHER2 to outstanding research. The winner of the competition will be awarded £250.

The winning image or video, along with a selection of other entries, will also be featured on the ARCHER2 website and in EPCC and ARCHER2 publications. Credit will be given to the entrant in all cases.

Key Details

  • Competition Opens: 8th August 2022
  • Submission Deadline: 16 September 2022
  • Judging: October/November 2022
  • Prizes:
    • Best image : £150
    • Best video : £150
    • Best early career researcher submission : £150
    • Overall winner, selected from the above three winners : additional £100

Full details and entry form:

Access to HPC Call

Access to HPC Call (EPSRC remit only) opened 4th July.
ARCHER2 or Tier-2 computing resource for a maximum duration of one year and a minimum of 4000 CU.
TA Deadline - 20th September 16:00
Submit Deadline - 18th October 16:00
More details an application forms

Recently added Known Issues

The “Known Issues” page of the ARCHER2 Documentation lists all current open known issues including a description of the issue, its symptoms and any work-arounds.

  • No recent issues

Upcoming ARCHER2 Training

  • Message-passing Programming with MPI, Online, always-open self-service course
  • Shared Memory Programming with OpenMP, Online, always-open self-service course
  • QM/MM with GROMACS + CP2K, Online, Always open - self-service course
  • Performance of different routing protocols on ARCHER2: OpenFabrics and UCX - (Postponed from 20th July), Online webinar, Wednesday date 17th August 2022 15:00 - 16:00 BST
  • Efficient Parallel IO, Online, 23 August 2022 09:30 - 16:30 BST
  • Introduction to OpenMP, Online, 30th & 31st August, 6th September 2022 09:00 - 17:00 BST
  • Debugging and Optimizing Parallel Codes with Arm Forge - Debugging and DDT, Online webinar, Wednesday 31st August 2022 15:00 - 16:00 BST
  • ARCHER2 for Software Developers, Online, 1 - 2 September 2022 10:00 - 16:00 BST
  • Debugging and Optimizing Parallel Codes with Arm Forge - Performance optimization, MAP, and PR, Online webinar, Wednesday 7th September 2022 15:00 - 16:00 BST
  • ARCHER2 for Package Users, Online, 13 October 2022 10:00 - 16:00 BST

Further details


Recordings of past courses and virtual tutorials can be found here: