Re: Does perf support different length of user-space hw_breakpoint?

[Jiri Olsa]

On Mon, May 12, 2014 at 03:52:54PM +0800, xiakaixu wrote:
> Hi guys,
> 
> Does perf support different length of user-space hw_breakpoint,
> such as  HW_BREAKPOINT_LEN_1/HW_BREAKPOINT_LEN_2/HW_BREAKPOINT_LEN_4/
> HW_BREAKPOINT_LEN_8?
> 
> Seems perf only support HW_BREAKPOINT_LEN_4/sizeof(long)
> by default from the source code and simple test.

right..

        /*
         * We should find a nice way to override the access length
         * Provide some defaults for now
         */
        if (attr.bp_type == HW_BREAKPOINT_X)
                attr.bp_len = sizeof(long);
        else
                attr.bp_len = HW_BREAKPOINT_LEN_4;

> 
> May I have your opinions if I want to trace different bytes of
> hw_breakpoint addr?

I guess that depends on what you want to do ;-)

jirka
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