Semi-automatic assessment of I/O behavior by inspecting the individual client-node timelines— an explorative study on 10^6 jobs

HPC applications with suboptimal I/O behavior interfere with well-behaving applications and lead to increased application runtime. In some cases, this may even lead to unresponsive systems and unfinished jobs. HPC monitoring systems can aid users and support staff to identify problematic behavior and support optimization of problematic applications. The key issue is how to identify relevant applications? A profile of an application doesn’t allow to identify problematic phases during the execution but tracing of each individual I/O is too invasive. In this work, we split the execution into segments, i.e., windows of fixed size and analyze profiles of them. We develop three I/O metrics to identify three relevant classes of inefficient I/O behaviors, and evaluate them on raw data of 1,000,000 jobs on the supercomputer Mistral. The advantages of our method is that temporal information about I/O activities during job runtime is preserved to some extent and can be used to identify phases of inefficient I/O. The main contribution of this work is the segmentation of time series and computation of metrics (Job-I/O-Utilization, Job-I/O-Problem-Time, and Job-I/O-Balance) that are effective to identify problematic I/O phases and jobs

Rational cohomology of algebraic solvable groups

If G is an affine algebraic group over a field F, and M is a finite-dimensional Fvector space, then M is a rational G-module if G acts on A4 via a morphism of algebraic groups over F: G p→AutF(M). An infinite-dimensional F-vector space M is a rational G-module if it is the union UiMi of finite-dimensional G-stable vector spaces M, such that the G-action on each of them is rational. In [S], Hochschild developed the foundations of rational cohomology, i.e., cohomology H*rat(G, M) in the category of rational G-modules. The most recent applications of rational cohomology (e.g. [4] and [6]) seem to be mainly restricted to groups defined over fields of nonzero characteristic. In this paper we will utilize the rational cohomology groups of algebraic solvable groups defined over the rational numbers Q. Our goal is to prove, for algebraic solvable G and for trivial Q-coefficients, an analog (Theorem 2.23) of the following theorem of Mostow [11,8.1] and Van Est [11,3.6.1]: If G is a connected simply connected real solvable Lie group and D is a discrete cocompact subgroup such that Adg(G) and Adg(D) have the same algebraic hulls, then the Lie algebra cohomology H*(gR, R) is isomorphic to the group cohomology H*(D), R) (trivial R-coefficients in both cases)

Leadership considerations for executive vice chairs, new chairs, and chairs in the 21st century.

The need to fulfill academic goals in the context of significant economic challenges, new regulatory requirements, and ever-changing expectations for leadership requires continuous adaptation. This paper serves as an educational resource for emerging leaders from the literature, national leaders, and other “best practices” in the following domains: 1. Mentorship; 2. Faculty Development; 3. Promotion; 4. Demonstrating value in each of the academic missions; 5. Marketing and communications; and 6. Barrier