9bbe3c433e
The PELT half-life is the time [ms] required by the PELT signal to build
up a 50% load/utilization, starting from zero. This time is currently
hardcoded to be 32ms, a value which seems to make sense for most of the
workloads.
However, 32ms has been verified to be too long for certain classes of
workloads. For example, in the mobile space many tasks affecting the
user-experience run with a 16ms or 8ms cadence, since they need to match
the common 60Hz or 120Hz refresh rate of the graphics pipeline.
This contributed so fare to the idea that "PELT is too slow" to properly
track the utilization of interactive mobile workloads, especially
compared to alternative load tracking solutions which provides a
better representation of tasks demand in the range of 10-20ms.
A faster PELT ramp-up time could give some advantages to speed-up the
time required for the signal to stabilize and thus to better represent
task demands in the mobile space. As a downside, it also reduces the
decay time, and thus we forget the load/utilization of sleeping tasks
(or idle CPUs) faster.
Fortunately, since the integration of the utilization estimation
support in mainline kernel:
commit
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.. | ||
calibrate.c | ||
do_mounts_dm.c | ||
do_mounts_initrd.c | ||
do_mounts_md.c | ||
do_mounts_rd.c | ||
do_mounts.c | ||
do_mounts.h | ||
init_task.c | ||
initramfs.c | ||
Kconfig | ||
Kconfig.gki | ||
main.c | ||
Makefile | ||
noinitramfs.c | ||
version.c |