service-config-manager performance issue

[Jiaqing Zhao]

Hi, all

When updating service status with service-config-manager, it always takes ~15s for the new status to be applied, which is much longer than it should be.

By inspecting the code, I found there is a 15s wait before updating service status in ServiceConfig::startServiceRestartTimer(). (https://github.com/openbmc/service-config-manager/blob/f2744893b77b9dd8903bb13113f4c3ef62c18f04/src/srvcfg_manager.cpp#L382)

The 15s-wait is added at first in commit 0084047 (https://github.com/openbmc/service-config-manager/commit/0084047d008fd0ac36f09a232f67ff2fc5314b53).

I've tested service-config-manager works as expected with the wait removed, and it only takes ~1s for the settings being applied, shall we remove it? And I'd like to ask what is the purpose of this wait to double confirm if removing it will bring any side effect.

Thanks,
Jiaqing