[systemd-devel] Why systemd-nspawn is slower than docker, podman and qemu?! how to Improve nspawn performance?

[Badr Elmers]

Tomasz Torcz
In fact I m just comparing containers, I have no need yet for context
switch, but I hope to understand why nspawn is slower and if there is
something I can do to improve it, for example disabling spectre/meltdown
mitigations improved nspawn a lot, so I was wondering if there is something
else I can do to make nspawn as quick as podman/docker/qemu.
Mantas Mikulėnas
I tested with  Export SYSTEMD_SECCOMP=0
no improvement, I still get the same result
thank you,
badr

On Mon, Jan 25, 2021 at 1:40 PM Badr Elmers <badrelmers at gmail.com> wrote:

> I tested with  Export SYSTEMD_SECCOMP=0
> no improvement, I still get the same result
> thank you,
> badr
>
> On Mon, Jan 25, 2021 at 1:14 PM Mantas Mikulėnas <grawity at gmail.com>
> wrote:
>
>> On Mon, Jan 25, 2021, 12:56 Badr Elmers <badrelmers at gmail.com> wrote:
>>
>>> Hi,
>>> Why nspawn is slow compared to docker podman and even qemu?!
>>> CPU tasks take twice of the time it takes in docker, podman or qemu
>>>
>>> here I filled a request to improve nspawn performance which contain the
>>> steps and the full test result:
>>> https://github.com/systemd/systemd/issues/18370
>>>
>>> Do you know why systemd-nspawn is slower? how can I improve it?
>>>
>>> thank you
>>>
>>>
>>>
>> Have you tried completely *disabling* the syscall filtering and all other
>> seccomp-based features? Export SYSTEMD_SECCOMP=0 before running nspawn and
>> check if it makes any difference...
>>
>
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