Christophe LEROY <christophe.le...@c-s.fr> writes:
> Hi Anton,
>
> Le 04/04/2017 à 00:00, Anton Blanchard a écrit :
>> Hi Christophe,
>>
>>>> - if (user_mode(regs))
>>>> + if (!is_exec && user_mode(regs))
>>>
>>> Shouldn't it also check 'is_write' ?
>>> If it is a store, is_write should be set, shouldn't it ?
>>
>> Thanks, Ben had the same suggestion. I'll add that further optimisation
>> in a subsequent patch.
>>
>
> For your information, I made some benchmark test using 'perf stat' with
> your app on MPC8321 and MPC885, and I got the following results:
MPC8321:
before 47386 faults
after 35181 faults -12205
is_write 35181 faults -12205
So that's good.
MPC885:
before: 176067 dTLB-load-misses
52722 iTLB-load-misses
25718 faults
after: 152462 dTLB-load-misses -23605
52715 iTLB-load-misses -7
19611 faults -6107
is_write: 147162 dTLB-load-misses -28905
52716 iTLB-load-misses -6
19610 faults -6108
Also good, and shows that is_write idea would be even better.
cheers
