Re: [PATCH 2/3] perf callchain: Stop resolving callchains after invalid address

Jiri Olsa
2015-11-26T15:59:04Z

On Thu, Nov 26, 2015 at 08:48:17AM -0700, David Ahern wrote:
> On 11/26/15 8:00 AM, Namhyung Kim wrote:
> >Hi David,
> >
> >On Thu, Nov 26, 2015 at 06:14:57AM -0700, David Ahern wrote:
> >>On 11/26/15 12:08 AM, Namhyung Kim wrote:
> >>>@@ -528,11 +529,16 @@ int main(int argc, const char **argv)
> >>> {
> >>> const char *cmd;
> >>> char sbuf[STRERR_BUFSIZE];
> >>>+ int min_addr;
> >>>
> >>> /* The page_size is placed in util object. */
> >>> page_size = sysconf(_SC_PAGE_SIZE);
> >>> cacheline_size = sysconf(_SC_LEVEL1_DCACHE_LINESIZE);
> >>>
> >>>+ if (sysctl__read_int("vm/mmap_min_addr", &min_addr) < 0)
> >>
> >>This assumes the record and analysis are done on the same system.
> >
> >Right. Maybe we can just use minimal size (or page size?) or save and
> >pass it through somewhere in the feature bit?
>
> no preference, but it should work with cross arch analysis as well (e.g.,
> record on arm/ppc and analysis on x86)

I think we should store it in perf.data in features, but seems
like a waste to spend one bit just for this number.

I remember commenting on new CPU related FEATURE data, that would contain
cpu specific data in extensible form like TAG,VALUE,TAG,VALUE..

but I think the design changed or something, because I cannot find it in now ;-)

maybe we could add something like that

jirka