Dear Takashi, On 04/24/18 14:15, Takashi Iwai wrote:
On Tue, 24 Apr 2018 13:59:58 +0200, Paul Menzel wrote:
On 04/23/18 14:33, Takashi Iwai wrote:On Mon, 23 Apr 2018 14:30:36 +0200, Paul Menzel wrote:On 04/23/18 14:21, Takashi Iwai wrote:On Mon, 23 Apr 2018 14:05:52 +0200, Paul Menzel wrote:From: Paul Menzel <pmenzel@xxxxxxxxxxxxx> 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 <pmenzel@xxxxxxxxxxxxx>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?Usually perf would help, but even a simple printk() should suffice to see what's going on there :)Please find the messages for a 23 ms run below, and the debug patch attached.[ 2.996238] calling azx_driver_init+0x0/0xfe4 [snd_hda_intel] @ 214 [ 3.009838] calling rtl8169_pci_driver_init+0x0/0x1000 [r8169] @ 217 [ 3.009904] r8169 Gigabit Ethernet driver 2.3LK-NAPI loaded [ 3.010721] random: get_random_bytes called from ipv6_regen_rndid+0x2c/0x100 with crng_init=1 [ 3.011283] r8169 0000:03:00.0 eth0: RTL8168e/8111e at 0x(ptrval), bc:5f:f4:c8:d3:98, XID 0c200000 IRQ 26 [ 3.011289] r8169 0000:03:00.0 eth0: jumbo features [frames: 9200 bytes, tx checksumming: ko] [ 3.013876] initcall rtl8169_pci_driver_init+0x0/0x1000 [r8169] returned 0 after 3917 usecs [ 3.031754] calling pcspkr_platform_driver_init+0x0/0x1000 [pcspkr] @ 221 [ 3.031904] input: PC Speaker as /devices/platform/pcspkr/input/input4 [ 3.032288] initcall pcspkr_platform_driver_init+0x0/0x1000 [pcspkr] returned 0 after 508 usecs [ 3.034795] calling psmouse_init+0x0/0x7c [psmouse] @ 220 [ 3.034903] initcall psmouse_init+0x0/0x7c [psmouse] returned 0 after 87 usecs [ 3.043051] random: get_random_u32 called from cache_random_seq_create+0xa3/0x1f0 with crng_init=1 [ 3.043154] random: get_random_u32 called from cache_alloc_refill+0x5bb/0x13d0 with crng_init=1 [ 3.043187] random: get_random_u32 called from cache_random_seq_create+0xa3/0x1f0 with crng_init=1 [ 3.043198] random: get_random_u32 called from cache_alloc_refill+0x5bb/0x13d0 with crng_init=1 [ 3.043229] random: get_random_u32 called from cache_random_seq_create+0xa3/0x1f0 with crng_init=1 [ 3.043265] random: get_random_u32 called from cache_alloc_refill+0x5bb/0x13d0 with crng_init=1 [ 3.043429] random: get_random_u32 called from cache_random_seq_create+0xa3/0x1f0 with crng_init=1 [ 3.043479] random: get_random_u32 called from cache_alloc_refill+0x5bb/0x13d0 with crng_init=1 [ 3.043749] random: get_random_bytes called from key_alloc+0x1fc/0x5e0 with crng_init=1 [ 3.043973] random: get_random_u32 called from cache_random_seq_create+0xa3/0x1f0 with crng_init=1 [ 3.045483] random: get_random_u32 called from arch_rnd.part.2+0x18/0x40 with crng_init=1 [ 3.045501] random: get_random_u32 called from load_elf_binary+0x76a/0x1d20 with crng_init=1 [ 3.045507] random: get_random_u32 called from arch_align_stack+0x45/0x70 with crng_init=1 [ 3.045528] random: get_random_u32 called from arch_rnd.part.2+0x18/0x40 with crng_init=1 [ 3.045558] random: get_random_u32 called from cache_alloc_refill+0x5bb/0x13d0 with crng_init=1 [ 3.045771] random: get_random_u32 called from cache_random_seq_create+0xa3/0x1f0 with crng_init=1 [ 3.046127] random: get_random_u32 called from cache_alloc_refill+0x5bb/0x13d0 with crng_init=1 [ 3.046197] calling pcsp_init+0x0/0x1000 [snd_pcsp] @ 221 [ 3.046206] Error: Driver 'pcspkr' is already registered, aborting... [ 3.046337] initcall pcsp_init+0x0/0x1000 [snd_pcsp] returned -16 after 128 usecs [ 3.046348] random: get_random_u32 called from arch_align_stack+0x45/0x70 with crng_init=1 [ 3.046363] random: get_random_bytes called from load_elf_binary+0xaf8/0x1d20 with crng_init=1 [ 3.046383] random: get_random_u32 called from randomize_page+0x42/0x57 with crng_init=1 [ 3.047312] random: get_random_u32 called from cache_alloc_refill+0x5bb/0x13d0 with crng_init=1 [ 3.048151] random: get_random_u32 called from cache_random_seq_create+0xa3/0x1f0 with crng_init=1 [ 3.048638] random: get_random_u32 called from cache_alloc_refill+0x5bb/0x13d0 with crng_init=1 [ 3.054325] random: get_random_u32 called from copy_process.part.33+0x186/0x2100 with crng_init=1 [ 3.054371] random: get_random_u32 called from cache_alloc_refill+0x5bb/0x13d0 with crng_init=1 [ 3.067344] usb usb3: New USB device found, idVendor=1d6b, idProduct=0001, bcdDevice= 4.17 [ 3.067350] usb usb3: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 3.067353] usb usb3: Product: OHCI PCI host controller [ 3.067356] usb usb3: Manufacturer: Linux 4.17.0-rc2+ ohci_hcd [ 3.067359] usb usb3: SerialNumber: 0000:00:12.0 [ 3.067850] random: get_random_u32 called from cache_random_seq_create+0xa3/0x1f0 with crng_init=1 [ 3.067864] hub 3-0:1.0: USB hub found [ 3.067960] hub 3-0:1.0: 5 ports detected [ 3.068141] random: get_random_u32 called from cache_alloc_refill+0x5bb/0x13d0 with crng_init=1 [ 3.068618] 1 [ 3.068644] 2 [ 3.068953] 3 [ 3.068954] 4 [ 3.068955] 5 [ 3.068959] 6 [ 3.068960] 7 [ 3.068966] 8 [ 3.068967] 9 [ 3.069204] 1 [ 3.069217] 2 [ 3.069565] 3 [ 3.069566] 4 [ 3.069567] 5 [ 3.069568] 6 [ 3.069569] 7 [ 3.069581] 8 [ 3.069583] 9 [ 3.069774] random: get_random_u32 called from copy_process.part.33+0x186/0x2100 with crng_init=1 [ 3.069924] initcall azx_driver_init+0x0/0xfe4 [snd_hda_intel] returned 0 after 23153 usecsUnfortunately, it looks like the time stamps of the Linux kernel and the initcall_debug time do not match. From the Linux time stamps it should be 73 ms.Indeed. But even from this result, you can have a rough idea. As you can see, the most of time was spent before "1" point, which is the very beginning of azx_probe(). That is, the slowness is not in HD-audio driver probe itself. Rather it's likely because of parallel probing with other multiple devices.
I agree. But that also makes it clear, that the probe can be done in async task, doesn’t it?
Kind regards, Paul
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