lkml.org 
[lkml]   [2014]   [Nov]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH V3 3/3] perf tools: Construct LBR call chain
On Fri, Nov 14, 2014 at 08:44:12AM -0500, kan.liang@intel.com wrote:

SNIP

> + if (lbr) {
> + for (i = 0; i < chain_nr; i++) {
> + if (chain->ips[i] == PERF_CONTEXT_USER)
> + break;
> + }
> +
> + /* LBR only affects the user callchain */
> + if (i != chain_nr) {
> + struct branch_stack *lbr_stack = sample->branch_stack;
> + int lbr_nr = lbr_stack->nr;
> + /*
> + * LBR callstack can only get user call chain.
> + * The mix_chain_nr is kernel call chain
> + * number plus LBR user call chain number.
> + * i is kernel call chain number,
> + * 1 is PERF_CONTEXT_USER,
> + * lbr_nr + 1 is the user call chain number.
> + * For details, please refer to the comments
> + * in callchain__printf
> + */
> + int mix_chain_nr = i + 1 + lbr_nr + 1;
> +
> + if (mix_chain_nr > PERF_MAX_STACK_DEPTH) {
> + pr_warning("corrupted callchain. skipping...\n");
> + return 0;
> + }
> +
> + for (j = 0; j < mix_chain_nr; j++) {
> + if (callchain_param.order == ORDER_CALLEE) {
> + if (j < i + 1)
> + ip = chain->ips[j];
> + else if (j > i + 1)
> + ip = lbr_stack->entries[j - i - 2].from;
> + else
> + ip = lbr_stack->entries[0].to;
> + } else {
> + if (j < lbr_nr)
> + ip = lbr_stack->entries[lbr_nr - j - 1].from;
> + else if (j > lbr_nr)
> + ip = chain->ips[i + 1 - (j - lbr_nr)];
> + else
> + ip = lbr_stack->entries[0].to;
> + }
> +
> + err = add_callchain_ip(thread, parent, root_al,
> + cpumode, ip);
> + if (err)
> + goto exit;
> + }
> + return 0;
> + }
> + }

also could you please move whole block above into separated function?
Andi has another change for this function and it's becoming really big.

other then that I think it's ok IMO and I could ack next version

thanks,
jirka


\
 
 \ /
  Last update: 2014-11-17 17:01    [W:0.164 / U:0.984 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site