Date: Tue, 27 Apr 2010 12:53:57 -0400 From: Alexander Sack <pisymbol@gmail.com> To: John Baldwin <jhb@freebsd.org> Cc: Charles Owens <cowens@greatbaysoftware.com>, freebsd-hardware@freebsd.org Subject: Re: Minute+ delay between kernel load and initialization (solved!) Message-ID: <r2k3c0b01821004270953pc593863ahb25f08caf906c382@mail.gmail.com> In-Reply-To: <201004270945.33722.jhb@freebsd.org> References: <4B5478D1.4000900@greatbaysoftware.com> <201004201202.56275.jhb@freebsd.org> <g2l3c0b01821004261910we85fa505zc975200743e38a24@mail.gmail.com> <201004270945.33722.jhb@freebsd.org>
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On Tue, Apr 27, 2010 at 9:45 AM, John Baldwin <jhb@freebsd.org> wrote: > On Monday 26 April 2010 10:10:17 pm Alexander Sack wrote: >> On Tue, Apr 20, 2010 at 12:02 PM, John Baldwin <jhb@freebsd.org> wrote: >> > On Tuesday 20 April 2010 11:56:34 am Charles Owens wrote: >> >> On 4/20/2010 9:13 AM, John Baldwin wrote: >> >> > On Monday 19 April 2010 6:05:06 pm Charles Owens wrote: >> >> > >> >> >> On 1/18/2010 10:05 AM, Charles Owens wrote: >> >> >> >> >> >>> Hello, >> >> >>> >> >> >>> We have a new system based on the Intel S5520 motherboard that se= ems > to >> >> >>> work fine except during _every_ boot it pauses for about one minu= te > 15 >> >> >>> seconds just before any kernel initialization messages appear. = =A0 We > see >> >> >>> the loader appearing to complete its work (the kernel is loaded) = and >> >> >>> then... it sits. =A0Once it starts up again (with usual kernel-bo= ot >> >> >>> messages) it appears to boot normally (no error messages). >> >> >>> >> >> >>> This has been seen with both FreeBSD 8.0 and 7.1, using GENERIC > kernels. >> >> >>> =A0I'd appreciate any and all assistance in figuring this out. >> >> >>> >> >> >>> Boot output follows (happens to be from a PAE-enabled kernel) >> >> >>> >> >> >>> Thank you, >> >> >>> >> >> >>> Charles >> >> >>> >> >> >>> >> >> >>> >> >> >> [truncated] >> >> >> >> >> >> An answer to this was graciously provided by Titus Manea. =A0 For > details, >> >> >> see >> >> >> >> >> >> http://www.freebsd.org/cgi/query-pr.cgi?pr=3Di386/144956 >> >> >> >> >> > Interesting. =A0I do not see the long delay on Nehalem machines her= e. > =A0Would >> >> > either of you be able to debug this further? =A0You could maybe gra= b TSC >> > values >> >> > at various points during the early console probe and print out the >> > relevant >> >> > deltas after cninit() returns. =A0You could then move the TSC probe > points >> >> > around to pinpoint which operations are taking a long time. >> >> > >> >> >> >> John, >> >> >> >> I'm not going to have the cycles to look at this any time soon, >> >> unfortunately. =A0 But, just in case, how does one display TSC values= ? =A0We >> >> did try to enable the kernel debugger, but the delay happens _before_ >> >> the debugger prompt is available. >> >> >> >> We now think of this more as an issue seen with some particular >> >> motherboard/BIOS combinations .... initially the only thing we really >> >> had to go on was the fact that the behavior was seen on new >> >> Nehalem-based systems. >> > >> > You would have to patch the source to add various calls to rdtsc() tha= t > were >> > saved in some sort of global array. =A0Then, once the console was full= y >> > initialized you could print out the TSC deltas by walking the array an= d >> > printing out the delta between each pair of entries. =A0You could then= move > the >> > rdtsc() calls around on subsequent tests to narrow down where the paus= e is >> > happening. >> >> Sorry John, I completely missed this. =A0If you haven't done it already, >> I can look into it for sure. =A0I have several Nehalem machines that do >> this. =A0Its on my TODO list though I thought the kdb probe was the fix? >> =A0Is that NOT the fix? >> >> Just let me know, guys, > > Maxim has a patch for the atkbd driver that works in his testing. =A0I th= ink it > is on another thread however. Alright, I will take a look and do the same on my end as another datapoint. I have been waiting all day to get my hands on this box! :) -aps
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