29 May 2022 Perfchat Show Notes

notes-22-may-2022.md

29 May 2022 Perfchat Show Notes

News

• AMD announced Ryzen 7000, Zen4 - https://www.anandtech.com/show/17399/amd-ryzen-7000-announced-zen4-pcie5-ddr5-am5-coming-fall
• Blog article: Compilers may generate branches for straight-line code - https://kristerw.github.io/2022/05/24/branchless/
• Paper: Intel Labs developed a quantum toolchain - https://arxiv.org/abs/2202.11142

Discussion

• N log N and forget about it dynamic memory allocation
• Graviton 3 launch
• Apple OS Systems guru
• ASN lossless compression
• Clickhouse timeseries database
• Linux low latency tuning guide
• uftrace - x86 only
• abusing gdb for tracing
• fixed space stream statistics algorithms
• Redhat low latency setup
• Berger's Stabilizer
• Kernel settings for stable benchmarks via adress randomization
• Sandy Munro Benchmarking in the manufacturing industry - video 2 first 5 minutes discusses importance of measuring varience
• Comcast utility for simulating bad network connections. Could be used like Berger's Coz.
• Rich's Github - data encoding for video games and Starlink network.
• Detecting colocated VMs

Great discussion, thanks for all who attended! My biggest insight today was:

• Need for eBPF and C/ASM macros to insert stream statistics - counters, ring buffers, t-digest, min-sketch .... identify constant and low cardinality data for specialization - make it easy to get more fine grain timings.
• Need for a common timestamp log format. Flexible from L2 fetches up to global network latency.
• Extending Berger's Coz/Stabilizer to more IO surfaces.
• How useful it would be to tell the OS to slow down certain memory operations for Coz style profiling. Can we expose RAM DIMMS as some sort of RAID also?
• From last time - extending SOUPER to act more like COZ/Stabilizer in slowing code down or modifying space.