Stefan Koehler @OracleSK

Independent Oracle performance consultant and researcher. Internals geek. OakTable member. Oracle ACE Alum. Sym42. soocs.de Bavaria, Germany Joined October 2014

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Christoph Lutz @chris_skyflier

a month ago

lgwr: You have the control gdb: I have the control

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Stefan Koehler @OracleSK

a month ago

NOPs and shifting trampolines is a fun on-going story all the time (e.g. 2-byte NOP, 0x66 prefixed and eBPF) 🤓 blogs.oracle.com/linux/post/ksp…

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Christoph Lutz @chris_skyflier

2 months ago

If you've ever felt the need to manually control adaptive lgwr features, this gdb script's got you covered: t.ly/lJIW1 😎 It lets you enable and disable adaptive scalable lgwr, fast log file sync, and log parallelism. Highly experimental, of course! Example 👇

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Stefan Koehler @OracleSK

2 months ago

Hallo @Hosteurope Für was gibt es bei Euch das KIS, wenn Ihr dort sowieso keine geplanten Wartungen mehr ankündigt oder Störungen veröffentlicht?

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Stefan Koehler @OracleSK

3 months ago

Any reason why the OVA image of the Oracle Database Free 23.x Virtual Appliance is not updated anymore? 23.8 is out for quite a time now but the OVA image is still 23.7 (23.7.0.25.01)? Thank you. @GeraldVenzl

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Stefan Koehler @OracleSK

5 months ago

Details about Spectre v2 Mitigations and speculative executions 🤓 blogs.oracle.com/linux/post/und…

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Stefan Koehler @OracleSK

5 months ago

Well 🧐 cloudsek.com/blog/the-bigge…

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Christoph Lutz @chris_skyflier

6 months ago

For geeks: two bpftrace scripts to map UTS event and component names to their internal ids. t.ly/bGj0M t.ly/ypKuv Didn’t plan on it, but sometimes the rabbit hole chooses you... Turns out "oradebug doc" doesn't expose all trace events.

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Tanel Poder 🇺🇦 @TanelPoder

7 months ago

Profile Explorer is a tool for viewing CPU profiling traces collected through the Event Tracing for Windows (ETW) infrastructure on machines with x64 and ARM64 CPUs github.com/microsoft/prof…

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Christoph Lutz @chris_skyflier

8 months ago

It continues to amaze me time and again what bpf based tracing makes possible … been looking into Oracle write consistency and update restart mechanics recently and tinkered with a bpftrace script to detect restarts system-wide and in real-time: t.ly/MgyQ- 🤓

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Christoph Lutz @chris_skyflier

8 months ago

1/4 Interesting UPDATE restart variation: Oracle may try to update a row during the ALL LOCKED phase that wasn't returned and locked in the prior LOCK phase (row 0 in the example).

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Stefan Koehler @OracleSK

10 months ago

A visionary leader for a nation, and look at what we got: @bundeskanzler with his „Sparbuch“ and „debt fantasies“ 🫣

Nayib Bukele @nayibbukele

10 months ago

A visionary leader for a nation, and look at what we got: @bundeskanzler with his „Sparbuch“ and „debt fantasies“ 🫣

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Stefan Koehler @OracleSK

11 months ago

Since a few hours I am going down the CPU scaling governors/drivers rabbit hole - Oh boy this is a mess 😱 Love the term "Autonomous frequency scaling" with Intel CPUs and we all know what this means 😅 Can't set fixed perf mode with active intel_pstate wiki.archlinux.org/title/CPU_freq…

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Stefan Koehler @OracleSK

12 months ago

Hey sweetie - Ghidra with XCOFF loader/support blog.silentsignal.eu/2021/04/06/add… It was a little bit messy to get it compiled and running with Ghidra on Kali 2024.3 but we can finally start digging

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Tanel Poder 🇺🇦 @TanelPoder

a year ago

I will be speaking at the @eBPFsummit 2024 conference about a new way for approaching Linux system performance, with 0x.tools and eBPF! Free online event on September 11th, 2024 ebpf.io/summit-2024/ See you there!