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A comment on IBM CTO Sees Smaller Container Platforms Ahead. Parent comment

Re:IBM CTO Sees Smaller Container Platforms Ahead by rwmj on Tuesday December 31, 2019 @08:41AM (#21920909)
You end up with a self-contained application binary which runs anywhere that you could run a Linux kernel.

However it's different from embedding an initrd into a kernel image in several ways: The kernel is minimal, containing only the bits which are needed by your application or drivers required to run on the hardware. The application runs in kernel space and is linked with the kernel which gives you a nice performance boost because you never context switch (which is the driver behind the whole project actually). You can also call kernel functions which aren't syscalls, eg. for specialized memory management.

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Re:IBM CTO Sees Smaller Container Platforms Ahead by ahoka on Tuesday December 31, 2019 @10:14AM (#21921469)
What's so wrong with the context switch? You need to have some anyway if you want threads in your unikernel.
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Re:IBM CTO Sees Smaller Container Platforms Ahead by eyberg on Tuesday December 31, 2019 @10:27AM (#21921580)
This is a common misunderstanding. There are many different types of context switching and you need the context (heh!) To compare apples to apples.

Kernel to userland, thread to thread, process to process, kernel thread vs user thread, etc. It's conflated because different threading models and different kernel/userland separations exist.

Generally speaking (in linux) threads perform much much faster than switching processes.

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Re:IBM CTO Sees Smaller Container Platforms Ahead by rwmj on Wednesday January 01, 2020 @11:24AM (#21928700)
This is right, and the other mistake people make is measuring just the context switch, and not the many hundreds of thousands of cycles after the context switch spent repopulating the cache.
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Re:IBM CTO Sees Smaller Container Platforms Ahead by 0x445442 on Tuesday December 31, 2019 @09:42AM (#21921257)
64-bit DOS?
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Re:IBM CTO Sees Smaller Container Platforms Ahead by fock on Tuesday December 31, 2019 @12:18PM (#21922628)
but with permissions you can conveniently ovveride by default!
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Re:IBM CTO Sees Smaller Container Platforms Ahead by rwmj on Wednesday January 01, 2020 @11:20AM (#21928671)
It doesn't even make sense to think about permissions for unikernels. There is exactly one application running. The trust boundary is at the edge of this application/kernel/VM thing, not anywhere within it.
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