Greetings,
As you can see in the data below, my i4790 box used to default to the
powersave governor despite CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y, and
disallowed switching to ondemand. Post 5.8, powersave locks in at the
lowest freq available, and while ondemand becomes the default, it takes
a cross core scheduling performance hit compared to previous powersave.
On a positive note, schedutil, which I used to have cause to avoid,
seems to have improved a lot while I wasn't looking, and now actually
improving cross core performance a wee bit. Seems I should configure
stable 5.[89] kernels to use it as well.
taskset 0xc pipe-test 1
CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y defaults to
5.4.74 2.183264 usecs/loop -- avg 2.179480 917.7 KHz powersave,
ondemand not allowed
5.5.19 2.184331 usecs/loop -- avg 2.179776 917.5 KHz powersave,
ondemand not allowed
5.6.19 2.198156 usecs/loop -- avg 2.204380 907.3 KHz powersave,
ondemand not allowed
5.7.19 2.230582 usecs/loop -- avg 2.231981 896.1 KHz powersave,
ondemand not allowed
5.8.17 3.203949 usecs/loop -- avg 3.207272 623.6 KHz ondemand
5.8.17 12.840411 usecs/loop -- avg 12.898500 155.1 KHz ondemand ->
powersave
5.9.2 3.024442 usecs/loop -- avg 3.040023 657.9 KHz ondemand
5.9.2 12.348519 usecs/loop -- avg 12.299751 162.6 KHz ondemand ->
powersave
CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL=y due to db865272d9c4
5.10.gc2dc4c0 2.121057 usecs/loop -- avg 2.121487 942.7 KHz schedutil
note: 4.0 GHz perfect!
5.10.gc2dc4c0 2.987989 usecs/loop -- avg 2.988658 669.2 KHz schedutil ->
ondemand note: 2.9 GHz not so perfect
5.10.gc2dc4c0 12.447348 usecs/loop -- avg 12.475363 160.3 KHz schedutil ->
powersave note: 800 MHz heeelp meee
5.10.gc2dc4c0 2.135548 usecs/loop -- avg 2.137868 935.5 KHz schedutil ->
performance note: 4.0 GHz (obviously)
