Kernel: CPU Isolation and Bugs
-
CPU Isolation – Introduction – by SUSE Labs (part 1)
CPU isolation is a powerful set of features that can be found behind the settings for workloads which rely on specific and often extreme latency or performance requirements. Some DPDK (Data Plane Development Kit) usecases can cover such examples. However CPU isolation’s documentation and footnotes for many subtleties remain scattered at best if not lagging behind recent developments. It’s not always easy to sort out the benefits and tradeoffs hiding behind the existing range of tunings. Our series of articles aims at shedding some light and guide the users throughout this obscure Linux Kernel subsystem that we maintain both upstream and in our SLE15 products.
[...]
The role of a kernel is to provide elementary services in order to use the hardware resources through a unified interface. This is the ground on which your workload walks.
-
Changing One "If" To "While" Caused An Unexpected Shift In A Kernel Benchmark This Week
Several months back you may recall that Linux 5.9 kernel regression we noted that in turn was bisected to code introduced by Linus Torvalds around page lock fairness. That was ultimately worked out in time with allowing a control over the page lock (un)fairness to address the regressed workloads while being fair enough to satisfy his original change. But now this week for Linux 5.11, Linus Torvalds has again altered the behavior. It then ended up causing a PostgreSQL database server performance regression but fortunately any impact should be very minimal and hopefully not appearing in any real-world situation.
Linus this week merged his own patch, mm: make wait_on_page_writeback() wait for multiple pending writebacks. It comes as a fix for his original rewrite of the wait_on_page_bit_common() logic. The issue is seeing occasional reports of BUG_ON() assertions being triggered since that change. Linus ended up uncovering a race condition where the BUG_ON() happens. See that linked patch for all the technical details for those interested. Within the wait_on_page_writeback() function though the patch is just changing an if statement to a while and fixes the BUG_ON assertion that was happening.
- Login or register to post comments
- Printer-friendly version
- 3175 reads
- PDF version
More in Tux Machines
- Highlights
- Front Page
- Latest Headlines
- Archive
- Recent comments
- All-Time Popular Stories
- Hot Topics
- New Members
digiKam 7.7.0 is releasedAfter three months of active maintenance and another bug triage, the digiKam team is proud to present version 7.7.0 of its open source digital photo manager. See below the list of most important features coming with this release. |
Dilution and Misuse of the "Linux" Brand
|
Samsung, Red Hat to Work on Linux Drivers for Future TechThe metaverse is expected to uproot system design as we know it, and Samsung is one of many hardware vendors re-imagining data center infrastructure in preparation for a parallel 3D world. Samsung is working on new memory technologies that provide faster bandwidth inside hardware for data to travel between CPUs, storage and other computing resources. The company also announced it was partnering with Red Hat to ensure these technologies have Linux compatibility. |
today's howtos
|
Recent comments
1 year 11 weeks ago
1 year 11 weeks ago
1 year 11 weeks ago
1 year 11 weeks ago
1 year 11 weeks ago
1 year 11 weeks ago
1 year 11 weeks ago
1 year 11 weeks ago
1 year 11 weeks ago
1 year 11 weeks ago