Re: [PATCH 1/1] perf symbols: Allow lookups by symbol name too

[Frederic Weisbecker <fweisbec@gmail.com>]

On Fri, Dec 11, 2009 at 06:50:22PM -0200, Arnaldo Carvalho de Melo wrote:
> From: Arnaldo Carvalho de Melo <acme@redhat.com>
> 
> Configurable via symbol_conf.sort_by_name, so that the cost of an extra
> rb_node on all 'struct symbol' instances is not paid by tools that only
> want to decode addresses.
> 
> How to use it:
> 
> 	symbol_conf.sort_by_name = true;
> 	symbol_init(&symbol_conf);
> 
> 	struct map *map = map_groups__find_by_name(kmaps, MAP__VARIABLE, "[kernel.kallsyms]");
> 
> 	if (map == NULL) {
> 		pr_err("couldn't find map!\n");
> 		kernel_maps__fprintf(stdout);
> 	} else {
> 		struct symbol *sym = map__find_symbol_by_name(map, sym_filter, NULL);
> 		if (sym == NULL)
> 			pr_err("couldn't find symbol %s!\n", sym_filter);
> 		else
> 			pr_info("symbol %s: %#Lx-%#Lx \n", sym_filter, sym->start, sym->end);
> 	}
> 
> Looking over the vmlinux/kallsyms is common enough that I'll add a
> variable to the upcoming struct perf_session to avoid the need to use
> map_groups__find_by_name to get the main vmlinux/kallsyms map.
> 
> The above example looks on the 'variable' symtab, but it is just like
> that for the functions one.
> 
> Also the sort operation is done when we first use
> map__find_symbol_by_name, in a lazy way.



Thanks a lot. I'll give it a try soon :)