I wish I had checked “online” on R19.2, but have not looked at it…and am now at 19.3. The fast way to check:
cat `find /sys/devices/system/cpu -name 'online'`
Running this on my quad core Phenom II (x86_64) shows
cat `find /sys/devices/system/cpu -name 'online'`
1
1
1
0-3
I’m just guessing, but it seems the layout is that of a single cpu used to boot the system, plus 3 listed as enabled in SMP after boot. My R19.3 shows the same behavior as what you mentioned:
cat `find . -name 'online'`
1
0
0
0
0
So it does indeed look like flashing is leaving cores unused. What is interesting is that there is one extra core, corresponding to the jetson-tk1 “k1”, along with the 4 ARM Cortex A15 cores. Because core 0 is listed as the ARMv7, we know jetson-tk1 is not the boot core (if and only if my assumption above is correct).
So it seems we do need to do something to use all 4 ARM cores. Anyone with R19.2 still installed that can show the listing of this?
cat `find /sys/devices/system/cpu -name 'online'`
Don’t know if someone from nVidia will see this, but my R19.3 /proc/cmdline shows this:
console=ttyS0,115200n8 console=tty1 no_console_suspend=1 lp0_vec=2064@0xf46ff000 video=tegrafb mem=1862M@2048M memtype=255 ddr_die=2048M@2048M section=256M pmuboard=0x0177:0x0000:0x02:0x43:0x00 vpr=151M@3945M tsec=32M@3913M otf_key=c75e5bb91eb3bd947560357b64422f85 usbcore.old_scheme_first=1 core_edp_mv=1150 core_edp_ma=4000 tegraid=40.1.1.0.0 debug_uartport=lsport,3 power_supply=Adapter audio_codec=rt5640 modem_id=0 android.kerneltype=normal usb_port_owner_info=0 fbcon=map:1 commchip_id=0 usb_port_owner_info=0 lane_owner_info=6 emc_max_dvfs=0 touch_id=0@0 tegra_fbmem=32899072@0xad012000 board_info=0x0177:0x0000:0x02:0x43:0x00 root=/dev/mmcblk0p1 rw rootwait tegraboot=sdmmc gpt
I did flash my R19.3 kernel for the same thing plus network bridging and CDROM filesystems (under U-Boot instead of fastboot). If the problem is related to command line at boot, perhaps it is an oversight in U-Boot parameters which was not carried over from fastboot.
So what is the correct fix for this to have the cores available after flash without manually echoing 1 to the online files?