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1. Jumanji: The Case for Dynamic NUCA in the Datacenter

   https://doi.org/10.1109/MICRO50266.2020.00061  

   Schwedock, Brian C.; Beckmann, Nathan (October 2020, MICRO)

   null (Ed.)

   The datacenter introduces new challenges for computer systems around tail latency and security. This paper argues that dynamic NUCA techniques are a better solution to these challenges than prior cache designs. We show that dynamic NUCA designs can meet tail-latency deadlines with much less cache space than prior work, and that they also provide a natural defense against cache attacks. Unfortunately, prior dynamic NUCAs have missed these opportunities because they focus exclusively on reducing data movement.We present Jumanji, a dynamic NUCA technique designed for tail latency and security. We show that prior last-level cache designs are vulnerable to new attacks and offer imperfect performance isolation. Jumanji solves these problems while significantly improving performance of co-running batch applications. Moreover, Jumanji only requires lightweight hardware and a few simple changes to system software, similar to prior D-NUCAs. At 20 cores, Jumanji improves batch weighted speedup by 14% on average, vs. just 2% for a non-NUCA design with weaker security, and is within 2% of an idealized design. 

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2. Fast Fine-Grained Global Synchronization on GPUs

   https://doi.org/10.1145/3297858.3304055  

   Wang, Kai; Fussell, Don; Lin, Calvin (April 2019, Proceedings of the Twenty-Fourth International Conference on Architectural Support for Programming Languages and Operating Systems)

   This paper extends the reach of General Purpose GPU programming by presenting a software architecture that supports efficient fine-grained synchronization over global memory. The key idea is to transform global synchronization into global communication so that conflicts are serialized at the thread block level. With this structure, the threads within each thread block can synchronize using low latency, high-bandwidth local scratchpad memory. To enable this architecture, we implement a scalable and efficient message passing library. Using Nvidia GTX 1080 ti GPUs, we evaluate our new software architecture by using it to solve a set of five irregular problems on a variety of workloads. We find that on average, our solutions improve performance over carefully tuned state-of-the-art solutions by 3.6×. 

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3. Rearchitecting Linux Storage Stack for µs Latency and High Throughput

   Hwang, Jaehyun; Vuppalapati, Midhul; Peter, Simon; Agarwal, Rachit (January 2021, 15th USENIX Symposium on Operating Systems Design and Implementation (OSDI 21))

   null (Ed.)

   This paper demonstrates that it is possible to achieve μs-scale latency using Linux kernel storage stack, even when tens of latency-sensitive applications compete for host resources with throughput-bound applications that perform read/write operations at throughput close to hardware capacity. Furthermore, such performance can be achieved without any modification in applications, network hardware, kernel CPU schedulers and/or kernel network stack. We demonstrate the above using design, implementation and evaluation of blk-switch, a new Linux kernel storage stack architecture. The key insight in blk-switch is that Linux's multi-queue storage design, along with multi-queue network and storage hardware, makes the storage stack conceptually similar to a network switch. blk-switch uses this insight to adapt techniques from the computer networking literature (e.g., multiple egress queues, prioritized processing of individual requests, load balancing, and switch scheduling) to the Linux kernel storage stack. blk-switch evaluation over a variety of scenarios shows that it consistently achieves μs-scale average and tail latency (at both 99th and 99.9th percentiles), while allowing applications to near-perfectly utilize the hardware capacity. 

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4. Rearchitecting Linux Storage Stack for µs Latency and High Throughput

   Hwang, Jaehyun; Vuppalapati, Midhul; Peter, Simon; Agarwal, Rachit (January 2021, 15th USENIX Symposium on Operating Systems Design and Implementation (OSDI 21))

   null (Ed.)

   This paper demonstrates that it is possible to achieve μs-scale latency using Linux kernel storage stack, even when tens of latency-sensitive applications compete for host resources with throughput-bound applications that perform read/write operations at throughput close to hardware capacity. Furthermore, such performance can be achieved without any modification in applications, network hardware, kernel CPU schedulers and/or kernel network stack. We demonstrate the above using design, implementation and evaluation of blk-switch, a new Linux kernel storage stack architecture. The key insight in blk-switch is that Linux's multi-queue storage design, along with multi-queue network and storage hardware, makes the storage stack conceptually similar to a network switch. blk-switch uses this insight to adapt techniques from the computer networking literature (e.g., multiple egress queues, prioritized processing of individual requests, load balancing, and switch scheduling) to the Linux kernel storage stack. blk-switch evaluation over a variety of scenarios shows that it consistently achieves μs-scale average and tail latency (at both 99th and 99.9th percentiles), while allowing applications to near-perfectly utilize the hardware capacity. 

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5. Rearchitecting Linux Storage Stack for μs Latency and High Throughput

   Hwang, Jaehyun; Vuppalapati, Midhul; Peter, Simon; Agarwal, Rachit (July 2021, Usenix Symposium on Operating Systems Design and Implementation)

   null (Ed.)

   This paper demonstrates that it is possible to achieve µs-scale latency using Linux kernel storage stack, even when tens of latency-sensitive applications compete for host resources with throughput-bound applications that perform read/write operations at throughput close to hardware capacity. Furthermore, such performance can be achieved without any modification in applications, network hardware, kernel CPU schedulers and/or kernel network stack. We demonstrate the above using design, implementation and evaluation of blk-switch, a new Linux kernel storage stack architecture. The key insight in blk-switch is that Linux’s multi-queue storage design, along with multi-queue network and storage hardware, makes the storage stack conceptually similar to a network switch. blk-switch uses this insight to adapt techniques from the computer networking literature (e.g., multiple egress queues, prioritized processing of individual requests, load balancing, and switch scheduling) to the Linux kernel storage stack. blk-switch evaluation over a variety of scenarios shows that it consistently achieves µs-scale average and tail latency (at both 99th and 99.9th percentiles), while allowing applications to near-perfectly utilize the hardware capacity. 

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