On 10:04 Thu 15 Nov , Lee Jones wrote: > This patchset supplies a new tool which measures boottime inclusive > of bootloader involvement. It seems to be accurate and adds no > latency to the booting of the system. > > In the first round of testing we booted the kernel 3 times each with > boottime enabled and disabled. Actually, when it was disabled, the > code was completely removed from the kernel source and the kernel was > rebuilt. The difference between present & enabled and completely > removed was very little indeed. In fact, averaging out the 3 runs of > each, when boottime was enabled the system booted 4ms _faster_, go > figure! > > Enabled Disabled > 1st run 2.983093 2.985168 > 2nd run 2.973266 2.971801 > 3rd run 2.975402 2.987304 > Average 2.977254 2.981424 -0.004171 (-4ms) > > > For the next round of testing, we delayed the bootloader for varying > amounts of time, then started to remove key components from kernel > functionality to see if the boottime system would pick-up on them. > > /* Hang around in the bootloader for a while. */ > $ cat /sys/kernel/debug/boottime/summary > kernel: 42864 msecs > total: 42864 msecs > kernel: cpu0 system: 56% idle: 43% iowait: 0% irq: 0% > cpu1 system: 4% idle: 95% iowait: 0% irq: 0% > > /* Hang around in the bootloader for a smaller amount of time. */ > kernel: 12351 msecs > total: 12351 msecs > kernel: cpu0 system: 56% idle: 43% iowait: 0% irq: 0% > cpu1 system: 2% idle: 97% iowait: 0% irq: 0% > > /* Instant boot. (1st run) */ > kernel: 7833 msecs > total: 7833 msecs > kernel: cpu0 system: 55% idle: 44% iowait: 0% irq: 0% > cpu1 system: 3% idle: 96% iowait: 0% irq: 0% > > /* Instant boot. (2nd run) */ > kernel: 7817 msecs > total: 7817 msecs > kernel: cpu0 system: 53% idle: 46% iowait: 0% irq: 0% > cpu1 system: 8% idle: 91% iowait: 0% irq: 0% > > /* Instant boot. (3rd run) */ > kernel: 7747 msecs > total: 7747 msecs > kernel: cpu0 system: 56% idle: 42% iowait: 0% irq: 0% > cpu1 system: 2% idle: 97% iowait: 0% irq: 0% 7/8s? on a u9500 wow it's really slow
I do 2/3s here Best Regards. J. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
