linux-kernel - Re: [PATCH 11/12] perf tools: Reuse shared eBPF dso objects

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Message-ID: <20190417065127.GA17024@krava>
Date:   Wed, 17 Apr 2019 08:51:27 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Adrian Hunter <adrian.hunter@...el.com>
Cc:     Jiri Olsa <jolsa@...nel.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Andi Kleen <ak@...ux.intel.com>,
        Song Liu <songliubraving@...com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>
Subject: Re: [PATCH 11/12] perf tools: Reuse shared eBPF dso objects

On Wed, Apr 17, 2019 at 09:35:32AM +0300, Adrian Hunter wrote:
> On 16/04/19 7:01 PM, Jiri Olsa wrote:
> > The eBPF program can be loaded multiple times
> > with the same name (tag). We can share dso
> > objects for those programs.
> 
> Doesn't a eBPF program get recompiled differently every time it is loaded?

yes, but those with same tag are identical

jirka

> 
> > 
> > Link: http://lkml.kernel.org/n/tip-3damf8vq1dryhtpbk5b06jpt@git.kernel.org
> > Signed-off-by: Jiri Olsa <jolsa@...nel.org>
> > ---
> >  tools/perf/util/machine.c | 14 +++++++++++---
> >  1 file changed, 11 insertions(+), 3 deletions(-)
> > 
> > diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
> > index d4aa44489011..a60653827891 100644
> > --- a/tools/perf/util/machine.c
> > +++ b/tools/perf/util/machine.c
> > @@ -23,6 +23,7 @@
> >  #include "linux/hash.h"
> >  #include "asm/bug.h"
> >  #include "bpf-event.h"
> > +#include "dso.h"
> >  
> >  #include "sane_ctype.h"
> >  #include <symbol/kallsyms.h>
> > @@ -699,11 +700,18 @@ static int machine__process_ksymbol_register(struct machine *machine,
> >  
> >  	map = map_groups__find(&machine->kmaps, event->ksymbol_event.addr);
> >  	if (!map) {
> > -		map = dso__new_map(event->ksymbol_event.name);
> > -		if (!map)
> > +		struct dso *dso;
> > +
> > +		dso = dsos__findnew(&machine->dsos, event->ksymbol_event.name);
> > +		if (!dso)
> >  			return -ENOMEM;
> >  
> > -		map->start = event->ksymbol_event.addr;
> > +		map = map__new2(event->ksymbol_event.addr, dso);
> > +		if (!map) {
> > +			dso__put(dso);
> > +			return -ENOMEM;
> > +		}
> > +
> >  		map->end = map->start + event->ksymbol_event.len;
> >  		map_groups__insert(&machine->kmaps, map);
> >  	}
> > 
>