linux-kernel - Re: [PATCH v2 5/5] perf session: Load single file for analysis

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Date:   Tue, 5 Oct 2021 15:16:59 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Alexey Bayduraev <alexey.v.bayduraev@...ux.intel.com>
Cc:     Jiri Olsa <jolsa@...hat.com>, Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Alexander Antonov <alexander.antonov@...ux.intel.com>,
        Alexei Budankov <abudankov@...wei.com>,
        Riccardo Mancini <rickyman7@...il.com>
Subject: Re: [PATCH v2 5/5] perf session: Load single file for analysis

Em Tue, Oct 05, 2021 at 01:27:02PM +0300, Alexey Bayduraev escreveu:
> Adding reader EOF return code and moving the check of EOF state to
> reader__mmap. Adding reader OK and NODATA return codes to simplify
> the code and separating reading code of single event into
> reader__read_event function. Introducing read_event/remap loop
> in __perf_session__process_events.

You are listing a series of changes done into just one cset, isn't it
possible to break this down to ease review (now and when looking for
bugs in the future :) )?

- Arnaldo
 
> Suggested-by: Jiri Olsa <jolsa@...nel.org>
> Acked-by: Namhyung Kim <namhyung@...il.com>
> Reviewed-by: Riccardo Mancini <rickyman7@...il.com>
> Tested-by: Riccardo Mancini <rickyman7@...il.com>
> Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@...ux.intel.com>
> ---
>  tools/perf/util/session.c | 74 +++++++++++++++++++++++++--------------
>  1 file changed, 47 insertions(+), 27 deletions(-)
> 
> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index 6c825e4a9dfe..1915714747a1 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -2167,6 +2167,12 @@ typedef s64 (*reader_cb_t)(struct perf_session *session,
>  			   union perf_event *event,
>  			   u64 file_offset);
>  
> +enum {
> +	READER_OK,
> +	READER_NODATA,
> +	READER_EOF,
> +};
> +
>  struct reader_state {
>  	char	*mmaps[NUM_MMAPS];
>  	size_t	 mmap_size;
> @@ -2229,6 +2235,9 @@ reader__mmap(struct reader *rd, struct perf_session *session)
>  	char *buf, **mmaps = st->mmaps;
>  	u64 page_offset;
>  
> +	if (st->file_pos >= st->data_size)
> +		return READER_EOF;
> +
>  	mmap_prot  = PROT_READ;
>  	mmap_flags = MAP_SHARED;
>  
> @@ -2257,36 +2266,26 @@ reader__mmap(struct reader *rd, struct perf_session *session)
>  	mmaps[st->mmap_idx] = st->mmap_cur = buf;
>  	st->mmap_idx = (st->mmap_idx + 1) & (ARRAY_SIZE(st->mmaps) - 1);
>  	st->file_pos = st->file_offset + st->head;
> -	return 0;
> +	return READER_OK;
>  }
>  
>  static int
> -reader__process_events(struct reader *rd, struct perf_session *session,
> -		       struct ui_progress *prog)
> +reader__read_event(struct reader *rd, struct perf_session *session,
> +		   struct ui_progress *prog)
>  {
>  	struct reader_state *st = &rd->state;
> -	u64 size;
> -	int err = 0;
> +	int err = READER_OK;
>  	union perf_event *event;
> +	u64 size;
>  	s64 skip;
>  
> -remap:
> -	err = reader__mmap(rd, session);
> -	if (err)
> -		goto out;
> -	if (session->one_mmap) {
> -		session->one_mmap_addr   = rd->state.mmap_cur;
> -		session->one_mmap_offset = rd->state.file_offset;
> -	}
> -
> -more:
>  	event = fetch_mmaped_event(st->head, st->mmap_size, st->mmap_cur,
>  				   session->header.needs_swap);
>  	if (IS_ERR(event))
>  		return PTR_ERR(event);
>  
>  	if (!event)
> -		goto remap;
> +		return READER_NODATA;
>  
>  	session->active_decomp = &rd->decomp_data;
>  	size = event->header.size;
> @@ -2308,18 +2307,12 @@ reader__process_events(struct reader *rd, struct perf_session *session,
>  	st->head += size;
>  	st->file_pos += size;
>  
> -	err = __perf_session__process_decomp_events(session);
> -	if (err)
> -		goto out;
> +	skip = __perf_session__process_decomp_events(session);
> +	if (skip)
> +		err = skip;
>  
>  	ui_progress__update(prog, size);
>  
> -	if (session_done())
> -		goto out;
> -
> -	if (st->file_pos < st->data_size)
> -		goto more;
> -
>  out:
>  	session->active_decomp = &session->decomp_data;
>  	return err;
> @@ -2356,9 +2349,36 @@ static int __perf_session__process_events(struct perf_session *session)
>  	err = reader__init(&rd, &session->one_mmap);
>  	if (err)
>  		goto out_err;
> -	err = reader__process_events(&rd, session, &prog);
> -	if (err)
> +
> +	err = reader__mmap(&rd, session);
> +	if (err < 0) {
>  		goto out_err;
> +	} else if (err == READER_EOF) {
> +		err = -EINVAL;
> +		goto out_err;
> +	}
> +
> +	if (session->one_mmap) {
> +		session->one_mmap_addr   = rd.state.mmap_cur;
> +		session->one_mmap_offset = rd.state.file_offset;
> +	}
> +
> +	while (true) {
> +		if (session_done())
> +			break;
> +
> +		err = reader__read_event(&rd, session, &prog);
> +		if (err < 0) {
> +			goto out_err;
> +		} else if (err == READER_NODATA) {
> +			err = reader__mmap(&rd, session);
> +			if (err < 0)
> +				goto out_err;
> +			else if (err == READER_EOF)
> +				break;
> +		}
> +	}
> +
>  	/* do the final flush for ordered samples */
>  	err = ordered_events__flush(oe, OE_FLUSH__FINAL);
>  	if (err)
> -- 
> 2.19.0

-- 

- Arnaldo