On Mon, Mar 15, 2010 at 9:56 PM, Johan Corveleyn <jcor...@gmail.com> wrote:
> On Mon, Mar 15, 2010 at 6:18 PM, Ivan Zhakov <i...@visualsvn.com> wrote:
>> On Mon, Mar 15, 2010 at 17:01, C. Michael Pilato <cmpil...@collab.net> wrote:
>>> Philip Martin wrote:
>>>> Johan Corveleyn <jcor...@gmail.com> writes:
>>>>
>>>>> On Tue, Mar 9, 2010 at 8:04 PM, Julian Foad <julian.f...@wandisco.com>
>>>>> wrote:
>>>>>> On Sun, 2010-03-07, Stefan Fuhrman wrote:
>>>>>>> Speed up input stream processing in config parser and
>>>>>>> others that read single bytes from a stream.
>>>>>>>
>>>>>>> * subversion/libsvn_subr/subst.c
>>>>>>> (translated_stream_read): Add an optimized code path
>>>>>>> for single byte read requests.
>>>>>>>
>>>>>>> Patch by: Stefan Fuhrmann <stefanfuhrmann{_AT_}alice-dsl.de>
>>>>>> Committed in r921057.
>>>>> Any chance this could be backported to 1.6.x?
>>>>>
>>>>> This seems like a nice performance improvement with low impact on the
>>>>> rest of the code. Would be nice if this could be put out there as
>>>>> quickly as possible (i.e. not having to wait for 1.7) for users to
>>>>> enjoy ...
>>>>
>>>> Can you quantify the improvement? I don't suppose a GUI like
>>>> TortoiseSVN reads config files very often. Any improvement is lost in
>>>> the noise when I run the command line client on Linux. It doesn't
>>>> change the number of system calls reported by 'strace -c'.
>>>
>>> Do our servers (mod_dav_svn and svnserve) parse authz files using this
>>> codepath?
>> Yes, they use the same code.
>>
>>> How often? On a per-connection basis?
>> mod_dav_svn caches authz file per connection.
>
> I just tested with svnserve x fsfs. For every connection it uses this
> code to read:
> - fsfs.conf (from within find_repos -> svn_repos_open)
> - svnserve.conf and authz (from within find_repos -> load_configs).
> There's no caching whatsoever, these files are read everytime a client
> requests something.
>
> I have no idea of the real performance impact, but maybe I'll do some
> measurements later tonight ...
Hm, I can't find a measurable performance difference for reading these
conf files on the server. That is, with a default fsfs.conf,
svnserve.conf, and a quite small authz file.
Putting an apr_time_now at the start and the end of
svn_config__parse_file in config_file.c yields exactly the same time
at the start and the end. Both with and without Stefan Fuhrmann's
change.
I guess this was to be expected, since both fsfs.conf and
svnserve.conf are quite small. For authz I also used a nearly empty
config (just containing the default comments and one *=r rule). Maybe
someone should try this with a very large authz file to see if it
makes a difference?
Johan
