From: Jiri Olsa <jolsa@redhat.com>
To: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Namhyung Kim <namhyung@kernel.org>,
Andi Kleen <ak@linux.intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-perf-users@vger.kernel.org
Subject: Re: [PATCH v2 2/2]: perf record: enable asynchronous trace writing
Date: Mon, 27 Aug 2018 10:38:52 +0200 [thread overview]
Message-ID: <20180827083852.GF24695@krava> (raw)
In-Reply-To: <54cc11d7-3ef2-c856-052e-6e2c309ff743@linux.intel.com>
On Thu, Aug 23, 2018 at 07:47:01PM +0300, Alexey Budankov wrote:
SNIP
> static int record__mmap_read_evlist(struct record *rec, struct perf_evlist *evlist,
> bool overwrite)
> {
> u64 bytes_written = rec->bytes_written;
> - int i;
> - int rc = 0;
> + int i, rc = 0;
> struct perf_mmap *maps;
> + int trace_fd = rec->session->data->file.fd;
> + struct aiocb **mmap_aio = rec->evlist->mmap_aio;
> + int mmap_aio_size = 0;
> + off_t off;
>
> if (!evlist)
> return 0;
> @@ -546,14 +620,17 @@ 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;
>
> + off = lseek(trace_fd, 0, SEEK_CUR);
> +
with async write, do we need to query/set the offset like this
all the time?
could we just keep/update the offset value in the 'struct perf_data_file'
and skip both lseek calls?
jirka
SNIP
>
> + record__mmap_read_sync(trace_fd, mmap_aio, mmap_aio_size, rec);
> +
> + lseek(trace_fd, off, SEEK_SET);
> +
next prev parent reply other threads:[~2018-08-27 8:38 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-23 16:33 [PATCH v2 0/2]: perf: reduce data loss when profiling highly parallel CPU bound workloads Alexey Budankov
2018-08-23 16:42 ` [PATCH v2 1/2]: perf util: map data buffer for preserving collected data Alexey Budankov
2018-08-27 8:28 ` Jiri Olsa
2018-08-27 8:58 ` Alexey Budankov
2018-08-27 8:33 ` Jiri Olsa
2018-08-27 9:02 ` Alexey Budankov
2018-08-28 8:45 ` Jiri Olsa
2018-08-28 9:19 ` Alexey Budankov
2018-08-23 16:47 ` [PATCH v2 2/2]: perf record: enable asynchronous trace writing Alexey Budankov
2018-08-27 8:34 ` Jiri Olsa
2018-08-27 9:12 ` Alexey Budankov
2018-08-27 8:38 ` Jiri Olsa [this message]
2018-08-27 9:33 ` Alexey Budankov
2018-08-27 10:05 ` Namhyung Kim
2018-08-27 10:25 ` Alexey Budankov
2018-08-27 10:38 ` Jiri Olsa
2018-08-27 10:48 ` Alexey Budankov
2018-08-27 8:43 ` Jiri Olsa
2018-08-27 9:45 ` Alexey Budankov
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