I saw that when over clocking A31 with AnTuTu the PLL1 Tune changes. I have
no clue or any documentation as to what this her does (the function of its
bits).
Anyone has any idea?
Raanan
On Sunday, August 31, 2014 11:59:29 AM UTC+3, RFat wrote:
>
> Hi Siahrhei,
>
> Thank you for your suggestion. I believe I am turning on the cache by
> calling:
>
>
> void cpu_dcache_enable(void) {
>
> u32 reg ;
>
> reg = get_cr();
>
> timer_delay_ms(1) ;
>
> set_cr(reg | CR_C);
>
> }
>
>
> void cpu_icache_enable(void) {
>
> u32 reg ;
>
> reg = get_cr();
>
> timer_delay_ms(1) ;
>
> set_cr(reg | CR_I);
>
> }
>
>
> which I believe turn on/off C (CP15) bits.
>
>
>
> I installed Antutu on that hardware (melee a1000g) and managed to
> over-clock it to 1200Mhz and could make sure it was a real over clocking -
> meaning that the system indeed became faster.
>
>
> I guess PLL1 is not the only guy that should be dealt with - perhaps
> someone knows what else?
>
>
> I'll keep looking into this.
>
>
> Thanks again!
>
>
>
>
>
> On Thursday, August 28, 2014 10:13:45 AM UTC+3, Siarhei Siamashka wrote:
>>
>> On Mon, 25 Aug 2014 05:43:04 -0700 (PDT)
>> RFat <[email protected]> wrote:
>>
>> > Hi all,
>> >
>> > I am trying to overclock the A31 higher than 1008MHz
>>
>> Are you fine with the deterioration of reliability and/or overheating
>> under high load?
>>
>> > and I am getting deterioration in performance.
>> >
>> > The way I work is execute a small program from u-boot which redefines
>> the N
>> > multiplayer of PLL1 and then runs some CPU-intentive routine (to
>> measure
>> > performance).
>> >
>> > Here are the results I get (the N multiplier is given in the small
>> brackets
>> > starting from 18):
>> >
>> > CPU Freq = 864Mhz (18)
>> > run in 10Hz, 94ms
>> > PLL1 is ENABLED P:2 M:1 K:3 N:18 Sigma:0 Lock:0 Freq:432Mhz
>> coreclk:864Mhz
>> > CPU Freq = 912Mhz (19)
>> > run in 11Hz, 89ms
>> > PLL1 is ENABLED P:2 M:1 K:3 N:19 Sigma:0 Lock:0 Freq:456Mhz
>> coreclk:912Mhz
>> > CPU Freq = 960Mhz (20)
>> > run in 11Hz, 85ms
>> > PLL1 is ENABLED P:2 M:1 K:3 N:20 Sigma:0 Lock:0 Freq:480Mhz
>> coreclk:960Mhz
>> > CPU Freq = 1008Mhz (21)
>> > run in 12Hz, 81ms
>> > PLL1 is ENABLED P:2 M:1 K:3 N:21 Sigma:0 Lock:0 Freq:504Mhz
>> coreclk:1008Mhz
>> > CPU Freq = 1056Mhz (22)
>> > run in 12Hz, 77ms
>> > PLL1 is ENABLED P:2 M:1 K:3 N:22 Sigma:0 Lock:0 Freq:528Mhz
>> coreclk:1056Mhz
>> > CPU Freq = 1104Mhz (23)
>> > run in 9Hz, 101ms
>> > PLL1 is ENABLED P:2 M:1 K:3 N:23 Sigma:0 Lock:0 Freq:552Mhz
>> coreclk:1104Mhz
>> > CPU Freq = 1152Mhz (24)
>> > run in 9Hz, 101ms
>> > PLL1 is ENABLED P:2 M:1 K:3 N:24 Sigma:0 Lock:0 Freq:576Mhz
>> coreclk:1152Mhz
>> > CPU Freq = 1200Mhz (25)
>> > run in 9Hz, 101ms
>> > PLL1 is ENABLED P:2 M:1 K:3 N:25 Sigma:0 Lock:0 Freq:600Mhz
>> coreclk:1200Mhz
>> > CPU Freq = 1248Mhz (26)
>> > run in 9Hz, 101ms
>> > PLL1 is ENABLED P:2 M:1 K:3 N:26 Sigma:0 Lock:0 Freq:624Mhz
>> coreclk:1248Mhz
>> > CPU Freq = 1296Mhz (27)
>> > run in 9Hz, 101ms
>> > PLL1 is ENABLED P:2 M:1 K:3 N:27 Sigma:0 Lock:0 Freq:648Mhz
>> coreclk:1296Mhz
>> > CPU Freq = 1344Mhz (28)
>> > run in 9Hz, 101ms
>> > PLL1 is ENABLED P:2 M:1 K:3 N:28 Sigma:0 Lock:0 Freq:672Mhz
>> coreclk:1344Mhz
>> > CPU Freq = 1392Mhz (29)
>> > run in 9Hz, 101ms
>> > PLL1 is ENABLED P:2 M:1 K:3 N:29 Sigma:0 Lock:0 Freq:696Mhz
>> coreclk:1392Mhz
>> >
>> > As you can see, after 1008 (or 1056) there's a _decrease_ in
>> performance.
>>
>> I can see that the performance flattens out and remains at the same
>> 101ms level for your CPU-intensive routine.
>>
>> If you are running the code in u-boot from SRAM and the L1 cache is not
>> enabled, then the instructions fetch may become a bottleneck.
>>
>> > Does anyone knows how higher performance can be achieved?
>>
>> Maybe buy a different higher performance SoC or better optimize the
>> software?
>>
>> --
>> Best regards,
>> Siarhei Siamashka
>>
>
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