On 12/24/15, Konstantin Belousov <kostik...@gmail.com> wrote: > On Thu, Dec 24, 2015 at 08:29:20AM -0700, Ian Lepore wrote: >> We had exactly this symptom -- long delay with spincursor before >> loading the kernel -- on arm systems when we first enabled forth in >> loader. The problem turned out to be the fact that loader was running >> with instruction and data caches disabled, and it took about 90-100 >> seconds to parse the 547 lines of text (almost all useless) in >> /boot/defaults/loader.conf. We stripped that file down to the dozen or >> so lines that actually needed to be there and booting became much >> faster. Eventually we got the caches enabled in the prior-stage >> bootloader and it became really fast. > > It is highly unlikely that caches are the source of the slowness. On > x86, we rely on the firmware (BIOS or EFI) to properly configure both > DRAM controllers and caches. More, Intel considers the corresponding > controllers configuration recipes as highly secret and, even for BIOS > vendors, Intel provides the binary blob of code which does the config > magic, instead of the documentation. > > That said, loader runs in the unpaged protected mode but reflects BIOS > calls into the real mode. Quite possible, either the real mode is > slow on SkyLakes, or even more possible, the switch between real and > protected mode is slow, or the protected mode without paging enabled is > slow. Or might be the PCH lacks the ISA timer.
Seem like the issue is affects the legacy boot mode, in UEFI mode the system boots blazingly fast. When I have more time, I try to figure out what's the problem behind this issue. > > A developer needs the real machine to diagnose the cause. > _______________________________________________ firstname.lastname@example.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"