svn commit: r268984 - head/lib/libc/stdio

[Andrey Chernov]

On 22.07.2014 20:44, Andrey Chernov wrote:
> Producing physical writes on ftell cause great performance degradation.
> You should check for __SAPP flag before calling sflush to do this only
> for append-mode files.

BTW, I believe that sflush() should be completely eliminated even for
_SAPP case. Something like that instead:

if (fp->_flags & __SAPP) {
	pos = _sseek(fp, (fpos_t)0, SEEK_END);
	if (pos == -1)
     		return (1);
} else if (fp->_flags & __SOFF)
	pos = fp->_offset;
else {
        pos = _sseek(fp, (fpos_t)0, SEEK_CUR);
	if (pos == -1)
     		return (1);
}

> 
> On 22.07.2014 20:19, Pedro F. Giffuni wrote:
>> Author: pfg
>> Date: Tue Jul 22 16:19:01 2014
>> New Revision: 268984
>> URL: http://svnweb.freebsd.org/changeset/base/268984
>>
>> Log:
>>   ftello: return 1 when seeking offset on an append stream.
>>   
>>   Obtained from:	Apple Inc. (Libc 997.90.3)
>>   Phabric:	D442
>>   MFC after:	2 weeks
>>
>> Modified:
>>   head/lib/libc/stdio/ftell.c
>>
>> Modified: head/lib/libc/stdio/ftell.c
>> ==============================================================================
>> --- head/lib/libc/stdio/ftell.c	Tue Jul 22 16:10:56 2014	(r268983)
>> +++ head/lib/libc/stdio/ftell.c	Tue Jul 22 16:19:01 2014	(r268984)
>> @@ -97,6 +97,8 @@ _ftello(FILE *fp, fpos_t *offset)
>>  	 * Find offset of underlying I/O object, then
>>  	 * adjust for buffered bytes.
>>  	 */
>> +	if (__sflush(fp))	/* may adjust seek offset on append stream */
>> +		return (1);
>>  	if (fp->_flags & __SOFF)
>>  		pos = fp->_offset;
>>  	else {
>>
> 
> 


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