Dear Linux folks,
By mistake I built `XFRM_ESP` into the Linux kernel, resulting in
CONFIG_CRYPTO_SEQIV=y
CONFIG_CRYPTO_ECHAINIV=y
and also the Jitterentropy RNG to be built in.
CRYPTO_JITTERENTROPY=y
So, on the Asus F2A85-M PRO starting Linux 4.10-rc3 with
`initcall_debug`, the init method is run unconditionally, and it takes
17.5 ms, which is over ten percent of the overall 900 ms the Linux
kernel needs until loading the init process.
[ 0.300544] calling jent_mod_init+0x0/0x2c @ 1
[ 0.318438] initcall jent_mod_init+0x0/0x2c returned 0 after
17471 usecs
Looking at the output of systemd-bootchart, it looks like, that this
indeed delayed the boot a little, as the other init methods seem to be
ordered after it.
I am now building it as a module, but am wondering if the time can be
reduced to below ten milliseconds.
Kind regards,
Paul
Am Montag, 9. November 2020, 20:31:02 CET schrieb Paul Menzel:
Hi Paul,
> Dear Linux folks,
>
>
> By mistake I built `XFRM_ESP` into the Linux kernel, resulting in
>
> CONFIG_CRYPTO_SEQIV=y
> CONFIG_CRYPTO_ECHAINIV=y
>
> and also the Jitterentropy RNG to be built in.
>
> CRYPTO_JITTERENTROPY=y
>
> So, on the Asus F2A85-M PRO starting Linux 4.10-rc3 with
> `initcall_debug`, the init method is run unconditionally, and it takes
> 17.5 ms, which is over ten percent of the overall 900 ms the Linux
Hm, 17.5 / 900 = 2%, or am I missing something?
> kernel needs until loading the init process.
>
> [ 0.300544] calling jent_mod_init+0x0/0x2c @ 1
> [ 0.318438] initcall jent_mod_init+0x0/0x2c returned 0 after
> 17471 usecs
>
> Looking at the output of systemd-bootchart, it looks like, that this
> indeed delayed the boot a little, as the other init methods seem to be
> ordered after it.
>
> I am now building it as a module, but am wondering if the time can be
> reduced to below ten milliseconds.
What you see is the test whether the Jitter RNG has a proper noise source. The
function jent_entropy_init() is the cause of the operation. It performs 1024
times a test to validate the appropriateness of the noise source. You can
adjust that with the TESTLOOPCOUNT in this function. But I am not sure
adjusting is a wise course of action.
Ciao
Stephan
Dear Stephan,
Thank you for the quick reply.
Am 10.11.20 um 10:25 schrieb Stephan Mueller:
> Am Montag, 9. November 2020, 20:31:02 CET schrieb Paul Menzel:
>> By mistake I built `XFRM_ESP` into the Linux kernel, resulting in
>>
>> CONFIG_CRYPTO_SEQIV=y
>> CONFIG_CRYPTO_ECHAINIV=y
>>
>> and also the Jitterentropy RNG to be built in.
>>
>> CRYPTO_JITTERENTROPY=y
>>
>> So, on the Asus F2A85-M PRO starting Linux 4.10-rc3 with
>> `initcall_debug`, the init method is run unconditionally, and it takes
>> 17.5 ms, which is over ten percent of the overall 900 ms the Linux
>
> Hm, 17.5 / 900 = 2%, or am I missing something?
Indeed, that is embarrassing. My bad.
>> kernel needs until loading the init process.
>>
>> [ 0.300544] calling jent_mod_init+0x0/0x2c @ 1
>> [ 0.318438] initcall jent_mod_init+0x0/0x2c returned 0 after 17471 usecs
>>
>> Looking at the output of systemd-bootchart, it looks like, that this
>> indeed delayed the boot a little, as the other init methods seem to be
>> ordered after it.
>>
>> I am now building it as a module, but am wondering if the time can be
>> reduced to below ten milliseconds.
>
> What you see is the test whether the Jitter RNG has a proper noise source. The
> function jent_entropy_init() is the cause of the operation. It performs 1024
> times a test to validate the appropriateness of the noise source. You can
> adjust that with the TESTLOOPCOUNT in this function. But I am not sure
> adjusting is a wise course of action.
Out of curiosity, why 1024 and not, for example, 128 or 2048? Is there
some statistics behind it?
Kind regards,
Paul