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From: Jiri Olsa <jolsa@redhat.com>
To: Song Liu <songliubraving@fb.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"ast@kernel.org" <ast@kernel.org>,
	"daniel@iogearbox.net" <daniel@iogearbox.net>,
	Kernel Team <Kernel-team@fb.com>
Subject: Re: [PATCH v11 perf, bpf-next 7/9] perf tools: synthesize PERF_RECORD_* for loaded BPF programs
Date: Tue, 22 Jan 2019 20:15:55 +0100	[thread overview]
Message-ID: <20190122191555.GH27625@krava> (raw)
In-Reply-To: <101BF88D-2DA4-4B54-A710-D0641C427136@fb.com>

On Tue, Jan 22, 2019 at 06:38:56PM +0000, Song Liu wrote:

SNIP

> >> in perf_session__process_event, this happens right when processing
> >> buildids in 'perf record', and also in 'perf report', so that is
> >> something badly synthesized that hits perf.data for PERF_RECORD_KSYMBOL.
> > 
> > it's reproducible with simple:
> >  perf record -e cycles,instructions ls
> > 
> > as you said on irc, it's the machine->id_hdr_size size missing
> > there's one more glitch, attached patch fixes that for me
> > you can't use sizeof(struct ksymbol_event), because it includes
> > the name as well.. which screws the size
> > 
> > but I don't know that code that much.. might be still something
> > missing
> > 
> > jirka
> 
> Hi Arnaldo and Jiri,
> 
> Thanks for catching and fixing the bug. 
> 
> I guess the following is OK?
> 
>         *bpf_event = (struct bpf_event){
>                 .header = {
>                         .type = PERF_RECORD_BPF_EVENT,
>                         .size = sizeof(struct bpf_event),
>                 },
>                 .type = PERF_BPF_EVENT_PROG_LOAD,
>                 .flags = 0,
>                 .id = info.id,
>         };
> 
> as struct bpf_event doesn't have variable length name:
> 
>         struct bpf_event {
>                 struct perf_event_header header;
>                 u16 type;
>                 u16 flags;
>                 u32 id;
> 
>                 /* for bpf_prog types */
>                 u8 tag[BPF_TAG_SIZE];  // prog tag
>         };
> 
> Or we need similar fix? 

yep, looks good.. also don't forget to add the 'machine->id_hdr_size'

jirka

  reply	other threads:[~2019-01-22 19:16 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-17 16:15 [PATCH v11 perf, bpf-next 0/9] reveal invisible bpf programs Song Liu
2019-01-17 16:15 ` [PATCH v11 perf, bpf-next 1/9] perf, bpf: Introduce PERF_RECORD_KSYMBOL Song Liu
2019-01-17 16:15 ` [PATCH v11 perf, bpf-next 2/9] sync tools/include/uapi/linux/perf_event.h Song Liu
2019-01-17 16:15 ` [PATCH v11 perf, bpf-next 3/9] perf, bpf: introduce PERF_RECORD_BPF_EVENT Song Liu
2019-01-17 16:15 ` [PATCH v11 perf, bpf-next 4/9] sync tools/include/uapi/linux/perf_event.h Song Liu
2019-01-17 16:15 ` [PATCH v11 perf, bpf-next 5/9] perf util: handle PERF_RECORD_KSYMBOL Song Liu
2019-01-18 14:45   ` Arnaldo Carvalho de Melo
2019-01-17 16:15 ` [PATCH v11 perf, bpf-next 6/9] perf util: handle PERF_RECORD_BPF_EVENT Song Liu
2019-01-18 14:46   ` Arnaldo Carvalho de Melo
2019-01-17 16:15 ` [PATCH v11 perf, bpf-next 7/9] perf tools: synthesize PERF_RECORD_* for loaded BPF programs Song Liu
2019-01-18 14:46   ` Arnaldo Carvalho de Melo
2019-01-22 14:13     ` Arnaldo Carvalho de Melo
2019-01-22 14:31       ` Arnaldo Carvalho de Melo
2019-01-22 14:48         ` Arnaldo Carvalho de Melo
2019-01-22 14:51         ` Jiri Olsa
2019-01-22 14:58           ` Arnaldo Carvalho de Melo
2019-01-22 15:21             ` Jiri Olsa
2019-01-22 18:38               ` Song Liu
2019-01-22 19:15                 ` Jiri Olsa [this message]
2019-01-22 19:24                   ` Song Liu
2019-01-22 19:44                     ` Jiri Olsa
2019-01-24  9:49                     ` Arnaldo Carvalho de Melo
2019-01-17 16:15 ` [PATCH v11 perf, bpf-next 8/9] perf top: Synthesize BPF events for pre-existing " Song Liu
2019-01-17 16:15 ` [PATCH v11 perf, bpf-next 9/9] bpf: add module name [bpf] to ksymbols for bpf programs Song Liu

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