Hi, this is your Linux kernel regression tracker speaking. Top-posting for once, to make this easy accessible to everyone. @Rafael or any other @acpi/@pm developer: what's the status here? Neither in this thread nor in the bug ticket anything happened afaics. Or is a 100ms boot time increase considered "not a regression"? Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat) P.S.: As the Linux kernel's regression tracker I'm getting a lot of reports on my table. I can only look briefly into most of them and lack knowledge about most of the areas they concern. I thus unfortunately will sometimes get things wrong or miss something important. I hope that's not the case here; if you think it is, don't hesitate to tell me in a public reply, it's in everyone's interest to set the public record straight. #regzbot poke On 10.01.22 12:29, Paul Menzel wrote: > #regzbot introduced: v5.13..v5.14-rc1 > #regzbot link: https://bugzilla.kernel.org/show_bug.cgi?id=215419 > > > Dear Linux folks, > > > On the Intel T4500 laptop Acer TravelMate 5735Z with Debian > sid/unstable, there is a 100 ms introduced between Linux 5.10.46 and > 5.13.9, and is still present in Linux 5.15.5. > > [ 0.000000] microcode: microcode updated early to revision 0xa0b, > date = 2010-09-28 > [ 0.000000] Linux version 5.15.0-2-amd64 > (debian-kernel@xxxxxxxxxxxxxxxx) (gcc-11 (Debian 11.2.0-13) 11.2.0, GNU > ld (GNU Binutils for Debian) 2.37) #1 SMP Debian 5.15.5-2 (2021-12-18) > [ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-5.15.0-2-amd64 > root=UUID=e17cec4f-d2b8-4cc3-bd39-39a10ed422f4 ro quiet noisapnp > cryptomgr.notests random.trust_cpu=on initcall_debug log_buf_len=4M > […] > [ 0.262243] calling acpi_init+0x0/0x487 @ 1 > […] > [ 0.281655] ACPI: Enabled 15 GPEs in block 00 to 3F > [ 0.394855] ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff]) > […] > [ 0.570908] initcall acpi_init+0x0/0x487 returned 0 after 300781 > usecs > > I attached all the log files to the Kernel.org Bugzilla bug report > #215419 [1]. > > Unfortunately, I am unable to bisect the issue, as it’s not my machine, > and I do not have a lot of access to it. > > Using ftrace, unfortunately, I didn’t save all of them, I think the path is > > acpi_init() → acpi_scan_init() → acpi_bus_scan(ACPI_ROOT_OBJECT) > > But this path hasn’t changed as far as I can see. Anyway, from that > path, somehow > > acpi_bus_check_add_1() → acpi_bus_check_add() → … → > acpi_bus_check_add() → acpi_add_single_object() → acpi_bus_get_status() > > is called, and the `acpi_bus_get_status()` call takes 100 ms on the > system – also the cause for bug #208705 [2] –, but that code path wasn’t > taken before. > > Do you know from the top of your head, what changed? I am going to have > short access to the system every two weeks or so, so debugging is > unfortunately quite hard. > > What is already on my to-do list: > > 1. Use dynamic debug `drivers/acpi/scan.c` > 2. Trace older Linux kernel (5.10.46) to see the differences > 3. Booting some GNU/Linux system to test 5.11 (Ubuntu 20.10) and 5.12 > 4. Unrelated to the regression, but trace `acpi_bus_get_status()` to > understand the 100 ms delay to solve bug #208705 [2] > > > Kind regards, > > Paul > > > PS: Do you know of GNU/Linux live systems that are available for all > Linux kernel releases and have an initrd, that just stores/uploads the > output of `dmesg`? > > > [1]: https://bugzilla.kernel.org/show_bug.cgi?id=215419 > "100 ms regression in boottime before `ACPI: PCI Root Bridge [PCI0]" > [2]: https://bugzilla.kernel.org/show_bug.cgi?id=208705 > "boot performance: 100 ms delay in PCI initialization - Acer > TravelMate 5735Z" > >
