[lkml]   [2019]   [Jun]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v2 0/7] cpufreq support for Raspberry Pi
Am 06.06.19 um 16:22 schrieb Nicolas Saenz Julienne:
> Hi all,
> this aims at adding cpufreq support to the Raspberry Pi family of
> boards.
> The series first factors out 'pllb' from clk-bcm2385 and creates a new
> clk driver that operates it over RPi's firmware interface[1]. We are
> forced to do so as the firmware 'owns' the pll and we're not allowed to
> change through the register interface directly as we might race with the
> over-temperature and under-voltage protections provided by the firmware.
> Next it creates a minimal cpufreq driver that populates the CPU's opp
> table, and registers cpufreq-dt. Which is needed as the firmware
> controls the max and min frequencies available.

Here some figures from the Raspberry Pi 3 B+ as before/after comparison:

Dhrystone Benchmark 2.1 A7 32 Bit

 600 MHz, w/o Turbo (1): 1216.11 VAX MIPS
1400 MHz, w/o Turbo (2): 2839.67 VAX MIPS
1400 MHz, w   Turbo (3): 2839.45 VAX MIPS

Whetstone Single Precision C Benchmark  vfpv4 32 Bit

 600 MHz, w/o Turbo: 454.565 MWIPS
1400 MHz, w/o Turbo: 1062.494 MWIPS
1400 MHz, w   Turbo: 1061.723 MWIPS

Power consumption (32 bit, without Ethernet) with load ( cat /dev/zero )

 600 MHz, w/o Turbo: 2.48 W
1400 MHz, w/o Turbo: 3.2 W
1400 MHz, w   Turbo: 3.15 W

Note 1: This is the maximum performance before enabling any cpufreq driver.

Note 2: This is the maximum performance after enabling V2 of the cpufreq

Note 3: This is the maximum performance after enabling the initial
cpufreq driver

 \ /
  Last update: 2019-06-08 12:44    [W:0.174 / U:2.524 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site