linux-kernel - Re: [PATCH v2 3/4] perf record: enable runtime trace compression

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Message-ID: <20190221094333.GB10990@krava>
Date:   Thu, 21 Feb 2019 10:43:33 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Alexey Budankov <alexey.budankov@...ux.intel.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 3/4] perf record: enable runtime trace compression

On Wed, Feb 20, 2019 at 05:53:17PM +0300, Alexey Budankov wrote:
> 
> On 12.02.2019 16:08, Jiri Olsa wrote:
> > On Mon, Feb 11, 2019 at 11:23:40PM +0300, Alexey Budankov wrote:
> > 
> > SNIP
> > 
> >> @@ -774,6 +775,8 @@ static int record__mmap_read_evlist(struct record *rec, struct perf_evlist *evli
> >>  	struct perf_mmap *maps;
> >>  	int trace_fd = rec->data.file.fd;
> >>  	off_t off;
> >> +	struct perf_session *session = rec->session;
> >> +	perf_mmap__compress_fn_t compress_fn;
> >>  
> >>  	if (!evlist)
> >>  		return 0;
> >> @@ -785,6 +788,9 @@ static int record__mmap_read_evlist(struct record *rec, struct perf_evlist *evli
> >>  	if (overwrite && evlist->bkw_mmap_state != BKW_MMAP_DATA_PENDING)
> >>  		return 0;
> >>  
> >> +	compress_fn = (record__comp_enabled(rec) ?
> >> +		perf_session__zstd_compress : perf_session__zstd_copy);
> >> +
> > 
> > I don't follow what's the perf_session__zstd_copy function for..?
> 
> It bridges AIO without compression case.

so current state then.. why do we need new function for that?

jirka

> 
> Thanks,
> Alexey
> 
> > 
> > for !record__comp_enabled case we seem not to use it
> > and calling the current perf_mmap__push interface
> > 
> > however I dont see point to have this function at all
> > 
> > jirka
> > 
> > 
> >>  	if (record__aio_enabled(rec))
> >>  		off = record__aio_get_pos(trace_fd);
> >>  
> >> @@ -799,11 +805,21 @@ static int record__mmap_read_evlist(struct record *rec, struct perf_evlist *evli
> >>  				map->flush = MMAP_FLUSH_DEFAULT;
> >>  			}
> >>  			if (!record__aio_enabled(rec)) {
> >> -				if (perf_mmap__push(map, rec, record__pushfn) != 0) {
> >> -					if (sync)
> >> -						map->flush = flush;
> >> -					rc = -1;
> >> -					goto out;
> >> +				if (!record__comp_enabled(rec)) {
> >> +					if (perf_mmap__push(map, rec, record__pushfn) != 0) {
> >> +						if (sync)
> >> +							map->flush = flush;
> >> +						rc = -1;
> >> +						goto out;
> >> +					}
> >> +				} else {
> >> +					if (perf_mmap__pack(map, rec, record__pushfn,
> >> +							compress_fn, session) != 0) {
> >> +						if (sync)
> >> +							map->flush = flush;
> >> +						rc = -1;
> >> +						goto out;
> >> +					}
> > 
> > SNIP
> >