The Delay in UEFI Shell Entry

I did a lot of tests in past two weeks. Due to our tool issue, we must reboot system after testing one bit. The system took 24 seconds to reboot, but our one bit test just took 55 ~ 56 seconds. This is a heavy wasting for completing a test. I cannot do any improvements for this issue because I am not the owner of this function. However, I can do another way to decrease the boot time.

In original UEFI Shell, it waits 5 seconds to prevent from user wants to stop launching the "startup.nsh". If we can decrease this time, it can also reduce our test time.

The UEFI Shell Entry is in "Root\ShellPkg\Application\Shell\Shell.c". We can search the key word "UefiMain" and we can find the setting is in this "ProcessCommandLine" function. The setting is stored in the "ShellInfoObject.ShellInitSettings.Delay" variable.

After modifying this variable, we can just wait 1 second, this can decrease 4 seconds in our one bit test time. It is not bad. Just for fun.


2020/05/21 Update

I am a stupid man. We can use "argv" to set up this delay time. This information is described in "3.2 Invocation" of "UEFI_Shell Specification". We can pass "-delay n" to UEFI Shell.

I thought one question when I ate lunch. How do I pass "-delay n" in boot time?  I think this is a good question. I don't know right now !