Dear Takashi,
On 04/23/18 14:21, Takashi Iwai wrote:
On Mon, 23 Apr 2018 14:05:52 +0200, Paul Menzel wrote:From: Paul Menzel <[email protected]> Date: Sat, 24 Mar 2018 09:28:43 +0100 On an ASRock E350M1, with Linux 4.17-rc1 according to `initcall_debug` calling `azx_driver_init` takes sometimes more than a few milliseconds, and up to 200 ms. ``` [ 2.892598] calling azx_driver_init+0x0/0xfe4 [snd_hda_intel] @ 218 [ 2.943002] initcall azx_driver_init+0x0/0xfe4 [snd_hda_intel] returned 0 after 49195 usecs ``` Trying to execute the Linux kernel in less than 500 ms, this is quite a hold-up, and therefore request the probe from an async task. With this change, the test shows, that the function returns earlier. ``` [ 3.254800] calling azx_driver_init+0x0/0xfe4 [snd_hda_intel] @ 227 [ 3.254887] initcall azx_driver_init+0x0/0xfe4 [snd_hda_intel] returned 0 after 66 usecs ``` The same behavior is visible on a Dell OptiPlex 7010. The longer times seem to happen, when the module *e1000e* is probed during the same time. Signed-off-by: Paul Menzel <[email protected]>What actually took so long? Could you analyze further instead of blindly putting the flag?
Well, I am not sure. Could you please give me hints, how to debug this further? Is there some debug flag?
I am only aware of the Ftrace framework, but in my experience it also skews the timings quite a bit, so might not be the best choice.
Kind regards, Paul
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