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USENIX SREcon APAC 2022: Computing Performance: What's on the Horizon

Brendan Gregg

My personal opinion is that I don't see a widespread need for more capacity given horizontal scaling and servers that can already exceed 1 Tbyte of DRAM; bandwidth is also helpful, but I'd be concerned about the increased latency for adding a hop to more memory. Ford, et al., “TCP

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Analyzing a High Rate of Paging

Brendan Gregg

Reads usually have apps waiting on them; writes may not (write-back caching). biolatency From [bcc], this eBPF tool shows a latency histogram of disk I/O. total used free shared buff/cache available Mem: 64414 15421 349 5 48643 48409 Swap: 0 0 0. This is a 64-Gbyte memory system, and 48 Gbytes is in the page cache.

Cache 105
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How To Add eBPF Observability To Your Product

Brendan Gregg

biolatency Disk I/O latency histogram heat map. cachestat File system cache statistics line charts. runqlat CPU scheduler latency heat map. For a more recent example, I wrote cachestat(8) while on vacation in 2014 for use on the Netflix cloud, which was a mix of Linux 3.2 execsnoop New processes (via exec(2)) table.

Latency 145
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USENIX SREcon APAC 2022: Computing Performance: What's on the Horizon

Brendan Gregg

My personal opinion is that I don't see a widespread need for more capacity given horizontal scaling and servers that can already exceed 1 Tbyte of DRAM; bandwidth is also helpful, but I'd be concerned about the increased latency for adding a hop to more memory. Ford, et al., “TCP

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Cache-Control for Civilians

CSS Wizardry

To this end, having a solid caching strategy can make all the difference for your visitors. ?? How is your knowledge of caching and Cache-Control headers? That being said, more and more often in my work I see lots of opportunities being left on the table through unconsidered or even completely overlooked caching practices.

Cache 264
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Three Other Models of Computer System Performance: Part 1

ACM Sigarch

How many buffers are needed to track pending requests as a function of needed bandwidth and expected latency? Can one both minimize latency and maximize throughput for unscheduled work? These models are useful for insight regarding the basic computer system performance metrics of latency and throughput (bandwidth). Little’s Law.

Systems 60
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Three Other Models of Computer System Performance: Part 2

ACM Sigarch

How many buffers are needed to track pending requests as a function of needed bandwidth and expected latency? Can one both minimize latency and maximize throughput for unscheduled work? The M/M/1 queue will show us a required trade-off among (a) allowing unscheduled task arrivals, (b) minimizing latency, and (c) maximizing throughput.

Systems 53