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The most challenging thing for us is running a new enough kernel to get these features. While upgrading to a newer kernel isn't particularly hard, small compani
by helper 10y ago
The most challenging thing for us is running a new enough kernel to get these features. While upgrading to a newer kernel isn't particularly hard, small companies don't have a lot of engineering resources to run kernels that aren't maintained by their distro of choice (usually on the LTS release).
The good thing is this is solved simply by waiting long enough. The bad thing is most developers can't just pick this up today without a bunch of extra effort.
If you are looking for something you can use with old kernels you should definitely checkout Brendan's perf-tools repo[1]. It takes advantage of older kernel features and works with things as old as ubuntu 12.04.
*Edit: Fixed Brendan's name
[1]: https://github.com/brendangregg/perf-tools https://github.com/brendangregg/perf-tools
- technofiend 10y agoThis is the same problem shared by RedHat customers, although RH is great about backporting features to older kernels, I'm not sure they'll be able to move this to 3.x from 4.9. The price we pay for stability.
- 4ad 10y agoYou mean the price paid for stable kernel ABIs, so proprietary drivers can use them? The Linux kernel is the most safe operating system component to upgrade, mostly because the Linux kernel people care deeply about compatibility and not breaking user space. While it is still not free to upgrade, the cost is minimal compared to the cost (in real money, risk, security) of backporting major components to older kernels, like Red Hat is doing. Red Hat is maintaining old kernels for having a stable kernel ABI (among some other reasons), not for general "stability". Personally I run only CentOS, but always with a recent kernel, albeit usually a LTS one. Mostly to get exactly these type of features described in this article.
- technofiend 10y agoWell they show the same caution and care around curating their repositories and releasing security fixes, so in my opinion (you may disagree) they try to ensure stability beyond the kernel's ABI.
- jlgaddis 10y agoIndeed. The kernel is not the only component (of the complete system) that gets features backported. I, personally, am quite happy that I don't really have to worry that a routine "yum update" is going to break any of my installed applications.
- devonkim 10y agoOn the other side of the spectrum, companies highly averse to technical changes culturally (typical case in the F500) will avoid ever upgrading kernels, libraries, and tooling. It's how I've wound up spending days trying to compile C++11 and C++14 code with toolchains that would run on CentOS / RHEL 5 and 6. Using the JVM lets you side-step the shared library linkage compatibility issues at least, but when you need a new kernel for instrumentation it's an even harder sell to an antagonistic IT department that only wants 2 OSes and corresponding versions to exist in the world ideally - "Linux" and Windows.
- brendangregg 10y agoRight, thanks, my perf-tools are on the Netflix BaseAMI, and are my go-to tracing tools for 3.x and earlier 4.x kernels.
- cthalupa 10y agoAmazon enabled BPF flags in the Amazon Linux AMI with 2016.03, and generally seems to move to whatever the latest LTS kernel is when they release a new version. Since 4.9 is supposed to be the next LTS, if it gets out of RC fast enough, we could see 4.9 in the 2017.03 Amazon Linux AMI, which would be a pretty big win for those of us running workloads in the AWS cloud.