linux-kernel - Re: [PATCH v7 2/2]: perf record: enable asynchronous trace writing

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Message-ID: <af8cc53e-b6c3-9a28-6f66-45817b65badc@linux.intel.com>
Date:   Thu, 6 Sep 2018 14:57:16 +0300
From:   Alexey Budankov <alexey.budankov@...ux.intel.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v7 2/2]: perf record: enable asynchronous trace writing



On 06.09.2018 14:04, Jiri Olsa wrote:
> On Wed, Sep 05, 2018 at 10:39:25AM +0300, Alexey Budankov wrote:
> 
> SNIP
> 
>> -static int record__pushfn(void *to, void *bf, size_t size)
>> +static int record__pushfn(void *to, struct aiocb *cblock, void *data, size_t size)
>>  {
>> +	off_t off;
>>  	struct record *rec = to;
>> +	int ret, trace_fd = rec->session->data->file.fd;
>>  
>>  	rec->samples++;
>> -	return record__write(rec, bf, size);
>> +
>> +	off =
>> +	lseek(trace_fd, 0, SEEK_CUR);
>> +	lseek(trace_fd, off + size, SEEK_SET);
>> +
>> +	ret = record__aio_write(cblock, trace_fd, data, size, off);
>> +	if (!ret) {
>> +		rec->bytes_written += size;
>> +		if (switch_output_size(rec))
>> +			trigger_hit(&switch_output_trigger);
> 
> why do you need to call switch output from here?

Just preserved this logic from the serial implementation.

> 
> jirka
>