Messages in this thread |  | | Date | Fri, 12 Jun 2015 14:17:31 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH v7 06/10] trace: Add lock-free tracing_map |
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On Mon, 8 Jun 2015 16:32:05 -0500 Tom Zanussi <tom.zanussi@linux.intel.com> wrote:
> Add tracing_map, a special-purpose lock-free map for tracing. > > tracing_map is designed to aggregate or 'sum' one or more values > associated with a specific object of type tracing_map_elt, which
What is "elt"? I don't see it explained anywhere.
> is associated by the map to a given key. > > It provides various hooks allowing per-tracer customization and is > separated out into a separate file in order to allow it to be shared > between multiple tracers, but isn't meant to be generally used outside > of that context. > > The tracing_map implementation was inspired by lock-free map > algorithms originated by Dr. Cliff Click: > > http://www.azulsystems.com/blog/cliff/2007-03-26-non-blocking-hashtable > http://www.azulsystems.com/events/javaone_2007/2007_LockFreeHash.pdf > > Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
> +/** > + * tracing_map_update_sum - Add a value to a tracing_map_elt's sum > + * @elt: The tracing_map_elt
Not a very useful comment, as I have no idea what "elt" is.
I'll continue to review this patch about the mysterious element "elt".
-- Steve
> + * @i: The index of the given sum associated with the tracing_map_elt > + * @n: The value to add to the sum > + * > + * Add n to sum i associated with the specified tracing_map_elt > + * instance. The index i is the index returned by the call to > + * tracing_map_add_sum_field() when the tracing map was set up. > + */ > +void tracing_map_update_sum(struct tracing_map_elt *elt, unsigned int i, u64 n) > +{ > + atomic64_add(n, &elt->fields[i].sum); > +} > +
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