Re: [RFC PATCH v6 0/2] Make eBPF programs output data to perf

From: pi3orama
Date: Thu Aug 13 2015 - 17:37:12 EST




发自我的 iPhone

> 在 2015年8月14日,上午5:27,Alexei Starovoitov <ast@xxxxxxxxxxxx> 写道:
>
>> On 7/20/15 8:08 PM, He Kuang wrote:
>> Hi,
>>
>> Previous patch v5 url:
>> http://thread.gmane.org/gmane.linux.kernel/1995274
>>
>> The bugfix of dynamic array length in trace event goes to
>> kernel/git/rostedt/linux-trace.git ftrace/urgent and confirms that the
>> return value of __get_dynamic_array_len() is the total allocated
>> length of the dynamic array. For we print the bpf output data in byte
>> array from patch v5, that problem does not affect our patch any more,
>> but some comments in patch 1/2 is updated.
>>
>> Patch 2/2 is acked by Alexei.
>
> what is the status of it? If I remember correctly patch 1 was fixed
> differently in Steven's tree. Patch 2 probably needs refreshing?
>

I was thinking about whether to add a "type" field there, so we will have an explicit
mov const instruction before the call instruction, which can act as a mark. Also, if
we generate the type code automatically, a type field in this API can make things
easier since we don't need wrap the user structure in BPF stack. However, the
LLVM side is not ready yet, so we haven't post the new version.

Thank you.
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