Re: [RFC][PATCH 4/4] perf/events: Use helper functions in eventassignment to shrink macro size

[Peter Zijlstra]

On Thu, 2012-08-09 at 23:43 -0400, Steven Rostedt wrote:
> plain text document attachment
> (0004-perf-events-Use-helper-functions-in-event-assignment.patch)
> From: Steven Rostedt <srostedt@xxxxxxxxxx>
> 
> The functions that assign the contents for the perf software events are
> defined by the TRACE_EVENT() macros. Each event has its own unique
> way to assign data to its buffer. When you have over 700 events,
> that means there's 700 functions assigning data uniquely for each
> event.
> 
> By making helper functions in the core kernel to do the work
> instead, we can shrink the size of the kernel down a bit.
> 
> With a kernel configured with 707 events, the change in size was:
> 
>    text    data     bss     dec     hex filename
> 19966937        2594648 1945600 24507185        175f331 vmlinux-before
> 19924761        2594584 1945600 24464945        1754e31 vmlinux-after
> 
> That's a total of 42240 bytes, which comes down to 59 bytes per event.

Seems like good stuff.. one nit..


> +void perf_trace_event_submit(void *raw_data, struct ftrace_event_call *event_call,
> +                            struct perf_trace_event *pe)
> +{
> +       struct hlist_head *head;
> +
> +       head = this_cpu_ptr(event_call->perf_events);
> +       perf_trace_buf_submit(raw_data, pe->entry_size, pe->rctx, pe->addr,
> +                             pe->count, &pe->regs, head);
> +}

Can you make perf_trace_buf_submit() go away? Its reduced to a simple
fwd function and layering another wrapper on top seems like pushing it.
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