linux-kernel - Re: [PATCH V3 11/12] perf top: switch default mode to overwrite mode

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Message-ID: <20180111142608.GF16655@krava>
Date:   Thu, 11 Jan 2018 15:26:08 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     kan.liang@...el.com
Cc:     acme@...nel.org, peterz@...radead.org, mingo@...hat.com,
        linux-kernel@...r.kernel.org, wangnan0@...wei.com,
        jolsa@...nel.org, namhyung@...nel.org, ak@...ux.intel.com,
        yao.jin@...ux.intel.com
Subject: Re: [PATCH V3 11/12] perf top: switch default mode to overwrite mode

On Thu, Dec 21, 2017 at 10:08:53AM -0800, kan.liang@...el.com wrote:

SNIP

>  		.max_stack	     = sysctl_perf_event_max_stack,
>  		.sym_pcnt_filter     = 5,
> diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
> index 68146f4..56023e4 100644
> --- a/tools/perf/ui/browsers/hists.c
> +++ b/tools/perf/ui/browsers/hists.c
> @@ -638,8 +638,13 @@ int hist_browser__run(struct hist_browser *browser, const char *help)
>  			nr_entries = hist_browser__nr_entries(browser);
>  			ui_browser__update_nr_entries(&browser->b, nr_entries);
>  
> -			if (browser->hists->stats.nr_lost_warned !=
> -			    browser->hists->stats.nr_events[PERF_RECORD_LOST]) {
> +			/*
> +			 * Don't print lost events warning for perf top,
> +			 * because it is overwrite mode.
> +			 * Perf top is the only tool which has hbt timer.
> +			 */

I hate that warning, but still should it be ommited only for overwrite case?
also please separate this change from the rest of the patch

jirka

> +			if ((browser->hists->stats.nr_lost_warned !=
> +			    browser->hists->stats.nr_events[PERF_RECORD_LOST]) && !hbt) {
>  				browser->hists->stats.nr_lost_warned =
>  					browser->hists->stats.nr_events[PERF_RECORD_LOST];
>  				ui_browser__warn_lost_events(&browser->b);
> @@ -3203,7 +3208,8 @@ static int perf_evsel_menu__run(struct perf_evsel_menu *menu,
>  		case K_TIMER:
>  			hbt->timer(hbt->arg);
>  
> -			if (!menu->lost_events_warned && menu->lost_events) {
> +			if (!menu->lost_events_warned &&
> +			    menu->lost_events && !hbt) {
>  				ui_browser__warn_lost_events(&menu->b);
>  				menu->lost_events_warned = true;
>  			}
> -- 
> 2.5.5
>