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freebsd-dev/sys/conf/files.i386
Colin Percival c2705ceaeb x86: Speed up clock calibration 
Prior to this commit, the TSC and local APIC frequencies were calibrated
at boot time by measuring the clocks before and after a one-second sleep.
This was simple and effective, but had the disadvantage of *requiring a
one-second sleep*.

Rather than making two clock measurements (before and after sleeping) we
now perform many measurements; and rather than simply subtracting the
starting count from the ending count, we calculate a best-fit regression
between the target clock and the reference clock (for which the current
best available timecounter is used). While we do this, we keep track
of an estimate of the uncertainty in the regression slope (aka. the ratio
of clock speeds), and stop measuring when we believe the uncertainty is
less than 1 PPM.

In order to avoid the risk of aliasing resulting from the data-gathering
loop synchronizing with (a multiple of) the frequency of the reference
clock, we add some additional spinning depending upon the iteration number.

For numerical stability and simplicity of implementation, we make use of
floating-point arithmetic for the statistical calculations.

On the author's Dell laptop, this reduces the time spent in calibration
from 2000 ms to 29 ms; on an EC2 c5.xlarge instance, it is reduced from
2000 ms to 2.5 ms.

Reviewed by:	bde (previous version), kib
MFC after:	1 month
Sponsored by:	https://www.patreon.com/cperciva
Differential Revision:	https://reviews.freebsd.org/D33802
2022-01-12 12:34:07 -08:00

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# This file tells config what files go into building a kernel,
# files marked standard are always included.
#
# $FreeBSD$
#
# common files stuff between i386 and amd64
include "conf/files.x86"
# The long compile-with and dependency lines are required because of
# limitations in config: backslash-newline doesn't work in strings, and
# dependency lines other than the first are silently ignored.
#
cddl/dev/dtrace/i386/dtrace_asm.S optional dtrace compile-with "${DTRACE_S}"
cddl/dev/dtrace/i386/dtrace_subr.c optional dtrace compile-with "${DTRACE_C}"
crypto/aesni/aeskeys_i386.S optional aesni
crypto/des/arch/i386/des_enc.S optional netsmb
crypto/openssl/i386/aesni-x86.S optional ossl
crypto/openssl/i386/chacha-x86.S optional ossl
crypto/openssl/i386/poly1305-x86.S optional ossl
crypto/openssl/i386/sha1-586.S optional ossl
crypto/openssl/i386/sha256-586.S optional ossl
crypto/openssl/i386/sha512-586.S optional ossl
dev/agp/agp_ali.c optional agp
dev/agp/agp_amd.c optional agp
dev/agp/agp_amd64.c optional agp
dev/agp/agp_ati.c optional agp
dev/agp/agp_i810.c optional agp
dev/agp/agp_intel.c optional agp
dev/agp/agp_nvidia.c optional agp
dev/agp/agp_sis.c optional agp
dev/agp/agp_via.c optional agp
dev/ce/ceddk.c optional ce
dev/ce/if_ce.c optional ce
dev/ce/tau32-ddk.c optional ce \
compile-with "${NORMAL_C} ${NO_WCONSTANT_CONVERSION} ${NO_WMISLEADING_INDENTATION}"
dev/glxiic/glxiic.c optional glxiic
dev/glxsb/glxsb.c optional glxsb
dev/glxsb/glxsb_hash.c optional glxsb
dev/hyperv/vmbus/i386/hyperv_machdep.c optional hyperv
dev/le/if_le_isa.c optional le isa
dev/nctgpio/nctgpio.c optional nctgpio
dev/nfe/if_nfe.c optional nfe pci
dev/ntb/if_ntb/if_ntb.c optional if_ntb
dev/ntb/ntb_transport.c optional ntb_transport | if_ntb
dev/ntb/ntb.c optional ntb | ntb_transport | if_ntb | ntb_hw_amd | ntb_hw_intel | ntb_hw_plx | ntb_hw
dev/ntb/ntb_if.m optional ntb | ntb_transport | if_ntb | ntb_hw_amd | ntb_hw_intel | ntb_hw_plx | ntb_hw
dev/ntb/ntb_hw/ntb_hw_amd.c optional ntb_hw_amd | ntb_hw
dev/ntb/ntb_hw/ntb_hw_intel.c optional ntb_hw_intel | ntb_hw
dev/ntb/ntb_hw/ntb_hw_plx.c optional ntb_hw_plx | ntb_hw
dev/ntb/test/ntb_tool.c optional ntb_tool
dev/nvram/nvram.c optional nvram isa
dev/ofw/ofw_pcib.c optional fdt pci
dev/pcf/pcf_isa.c optional pcf
dev/random/ivy.c optional rdrand_rng !random_loadable
dev/random/nehemiah.c optional padlock_rng !random_loadable
dev/sbni/if_sbni.c optional sbni
dev/sbni/if_sbni_isa.c optional sbni isa
dev/sbni/if_sbni_pci.c optional sbni pci
dev/speaker/spkr.c optional speaker
dev/superio/superio.c optional superio isa
dev/syscons/scvesactl.c optional sc vga vesa
dev/syscons/scvgarndr.c optional sc vga
dev/tpm/tpm.c optional tpm
dev/tpm/tpm_acpi.c optional tpm acpi
dev/tpm/tpm_isa.c optional tpm isa
dev/uart/uart_cpu_x86.c optional uart
dev/viawd/viawd.c optional viawd
dev/vmd/vmd.c optional vmd
dev/acpi_support/acpi_wmi_if.m standard
dev/wbwd/wbwd.c optional wbwd
i386/acpica/acpi_machdep.c optional acpi
i386/acpica/acpi_wakeup.c optional acpi
acpi_wakecode.o optional acpi \
dependency "$S/i386/acpica/acpi_wakecode.S assym.inc" \
compile-with "${NORMAL_S}" \
no-obj no-implicit-rule before-depend \
clean "acpi_wakecode.o"
acpi_wakecode.bin optional acpi \
dependency "acpi_wakecode.o" \
compile-with "${OBJCOPY} -S -O binary acpi_wakecode.o ${.TARGET}" \
no-obj no-implicit-rule before-depend \
clean "acpi_wakecode.bin"
acpi_wakecode.h optional acpi \
dependency "acpi_wakecode.bin" \
compile-with "file2c -sx 'static char wakecode[] = {' '};' < acpi_wakecode.bin > ${.TARGET}" \
no-obj no-implicit-rule before-depend \
clean "acpi_wakecode.h"
acpi_wakedata.h optional acpi \
dependency "acpi_wakecode.o" \
compile-with '${NM} -n --defined-only acpi_wakecode.o | while read offset dummy what; do echo "#define $${what} 0x$${offset}"; done > ${.TARGET}' \
no-obj no-implicit-rule before-depend \
clean "acpi_wakedata.h"
#
i386/bios/smapi.c optional smapi
i386/bios/smapi_bios.S optional smapi
#i386/i386/apic_vector.s optional apic
i386/i386/bios.c standard
i386/i386/bioscall.s standard
i386/i386/bpf_jit_machdep.c optional bpf_jitter
i386/i386/copyout.c standard
i386/i386/db_disasm.c optional ddb
i386/i386/db_interface.c optional ddb
i386/i386/db_trace.c optional ddb
i386/i386/exec_machdep.c standard
i386/i386/elan-mmcr.c optional cpu_elan | cpu_soekris
i386/i386/elf_machdep.c standard
i386/i386/exception.s standard
i386/i386/gdb_machdep.c optional gdb
i386/i386/geode.c optional cpu_geode
i386/i386/in_cksum_machdep.c optional inet | inet6
i386/i386/initcpu.c standard
i386/i386/io.c optional io
i386/i386/k6_mem.c optional mem
i386/i386/locore.s standard no-obj
i386/i386/longrun.c optional cpu_enable_longrun
i386/i386/machdep.c standard
i386/i386/mem.c optional mem
i386/i386/minidump_machdep.c standard
i386/i386/minidump_machdep_pae.c standard
i386/i386/minidump_machdep_nopae.c standard
i386/i386/mp_clock.c optional smp
i386/i386/mp_machdep.c optional smp
i386/i386/mpboot.s optional smp
i386/i386/npx.c standard
i386/i386/perfmon.c optional perfmon
i386/i386/pmap_base.c standard
i386/i386/pmap_nopae.c standard
i386/i386/pmap_pae.c standard
i386/i386/ptrace_machdep.c standard
i386/i386/sigtramp.s standard
i386/i386/support.s standard
i386/i386/swtch.s standard
i386/i386/sys_machdep.c standard
i386/i386/trap.c standard
i386/i386/uio_machdep.c standard
i386/i386/vm86.c standard
i386/i386/vm_machdep.c standard
i386/pci/pci_cfgreg.c optional pci
i386/pci/pci_pir.c optional pci
isa/syscons_isa.c optional sc
isa/vga_isa.c optional vga
kern/imgact_aout.c optional compat_aout
kern/subr_sfbuf.c standard
libkern/divdi3.c standard
libkern/ffsll.c standard
libkern/flsll.c standard
libkern/memcmp.c standard
libkern/memset.c standard
libkern/moddi3.c standard
libkern/qdivrem.c standard
libkern/strlen.c standard
libkern/ucmpdi2.c standard
libkern/udivdi3.c standard
libkern/umoddi3.c standard
#
# x86 real mode BIOS support, required by dpms/pci/vesa
#
compat/x86bios/x86bios.c optional x86bios | dpms | pci | vesa
# Common files where we currently configure the system differently, but perhaps shouldn't
# config(8) doesn't have a way to force standard options, so we've been inconsistent
# about marking non-optional things 'standard'.
x86/acpica/madt.c optional acpi apic
x86/cpufreq/smist.c optional cpufreq
x86/isa/atpic.c optional atpic
x86/isa/elcr.c optional atpic | apic
x86/isa/isa.c optional isa
x86/isa/isa_dma.c optional isa
x86/x86/io_apic.c optional apic
x86/x86/local_apic.c optional apic
x86/x86/mptable.c optional apic
x86/x86/mptable_pci.c optional apic pci
x86/x86/msi.c optional apic pci
# Clock calibration subroutine; uses floating-point arithmetic
subr_clockcalib.o standard \
dependency "$S/kern/subr_clockcalib.c" \
compile-with "${CC} -c ${CFLAGS:C/^-O2$/-O3/:N-nostdinc} ${WERROR} -m80387 ${.IMPSRC}" \
no-implicit-rule \
clean "subr_clockcalib.o"
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