Re: [PATCH v3 0/8] pstore: Improve performance of ftrace backend with ramoops

[Joel Fernandes]

On Tue, Nov 15, 2016 at 2:14 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> On Tue, Nov 15, 2016 at 2:06 PM, Joel Fernandes <joelaf@xxxxxxxxxx> wrote:
>> Hi Kees,
>>
>> On Tue, Nov 15, 2016 at 1:36 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>>> On Tue, Nov 15, 2016 at 11:55 AM, Joel Fernandes <joelaf@xxxxxxxxxx> wrote:
>>>> Hi Kees,
>>>>
>>>> On Fri, Nov 11, 2016 at 2:21 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>>>>> Hi Joel,
>>>>>
>>>>> I've reorganized a bunch of the logic here. Since pstore is going to need
>>>>> the init_przs() logic for multiple pmsg przs, I wanted to get this in and
>>>>> make sure I was happy with how it looks. I figured this would reduce our
>>>>> round-trip time on reviews. :)
>>>>>
>>>>> Can you test this series and verify that it works as you're expecting? I've
>>>>> validated some basic behavior already, but don't have a good test-case for
>>>>> ftrace. What commands do you actually use for testing ftrace? I'd like to
>>>>> add something to my local tests.
>>>>
>>>> I normally do the following:
>>>>
>>>> dd if=/dev/urandom | pv | dd of=/dev/null
>>>>
>>>> and in parallel, I do a:
>>>> echo 1 > /sys/kernel/debug/pstore/record_ftrace
>>>>
>>>> and then check the throughput; and then reboot the system and do a
>>>> read out of /sys/fs/pstore/ ftrace file.
>>>
>>> Cool. Does something normally parse these? Lots of kernel addresses is
>>> all I see. ;)
>>>
>>
>> It should print symbol names if KALLSYMS is working properly as it
>> uses %pf (in pstore_ftrace_seq_show function).
>
> Hrm. No such luck for me, but it's clearly using pstore correctly, so
> I'm satisfied things are working along that path. :)

Tested your for-next/pstore branch and ftrace on pstore works fine.

Thanks!

Joel