Re: Testing 7.0 Beta: FFS still very slow when creating files

[christos%astron.com@localhost (Christos Zoulas)]

In article <20140825213735.GA14378%britannica.bec.de@localhost>,
Joerg Sonnenberger  <joerg%britannica.bec.de@localhost> wrote:
>On Mon, Aug 25, 2014 at 09:09:24PM +0000, Taylor R Campbell wrote:
>>    Date: Mon, 25 Aug 2014 20:02:44 +0200
>>    From: "J. Hannken-Illjes" <hannken%eis.cs.tu-bs.de@localhost>
>> 
>>    Short answer: it is -- reverting external/gpl3/gcc/dist/gcc/builtins.c
>>    from Rev. 1.3 to 1.2 brings back the old times which are the same as
>>    they were on NetBSD 6.
>> 
>>    Given that this test has many calls to ufs_lookup/cache_lookup using
>>    memcmp to check for equal filenames this is not a surprise.
>> 
>>    A rather naive "implementation" of memcmp (see below) drops the running
>>    time from ~15 sec to ~9 secs.  We should consider improving our memcmp.
>> 
>> Sounds reasonable to me, although it looks like GCC's old builtin
>> memcmp expansion actually failed to implement our specification: it
>> returns -1, 0, or +1, like your patch, rather than the difference of
>> the first differing bytes or zero as our man page specifies.  For most
>> uses it doesn't matter, of course, but we ought to make sure to follow
>> our own specification.
>
>memcmp is only supposed to provide the correct sign, not the difference.

Yes, according to TOG, not according to our documentation. Not that I advocate
to keep our documentation....

christos