> How do you propose that the parser should know, in advance, which parts
> of the authz and groups files it can discard unless it parses all of them?
By this point
<https://github.com/apache/subversion/blob/6fb211a2f84c9fe69025e16bc564d2f8dc343249/subversion/svnserve/serve.c#L4261>
b->client_info->tunnel_user is properly set only in the tunnel mode. I
think it can be passed to the svn_authz__parse(), which should become
slightly more intelligent passing stream and tunnel_user to specific
callbacks for the [groups] and the [aliases] sections. By default there are
no discovered groups. Surfing the group section parser should skip all
users except tunnel_user and already discovered groups, otherwise add such
group with relevant data to the set of discovered. Same for aliases.
Thus we will have parsed only groups related to a particular user and
svn_authz__parse() won't need to to expand all irrelevant groups
<https://github.com/apache/subversion/blob/f91051c82d38a732b546a84f4ead491514e81010/subversion/libsvn_repos/authz_parse.c#L1417>
(~3500k in my case) and expand every acl (~100 in my case) applying access
rules to all irrelevant users
<https://github.com/apache/subversion/blob/f91051c82d38a732b546a84f4ead491514e81010/subversion/libsvn_repos/authz_parse.c#L1452>
(~35k in my case).
Please correct me if I am naive somewhere.
ср, 11 сент. 2019 г. в 19:34, Sam Toliman <ivansduck_at_gmail.com>:
> Greetings,
>
> TLDR since 1.10 subversion loading acl file ~15x times slower, which leads
> in performance regression in tunnel mode used with svn+ssh scheme.
>
> https://subversion.apache.org/docs/release-notes/1.10#authzperf says that
> performance was improved, but we have discovered regression using large
> access files (>2Mb) (depersonalized:
> https://drive.google.com/file/d/1PP5n9BJkCs1Ssn47mHkI9dADPbo7DasJ/view).
>
> Problem can be localized and reproduced using svnauthz-validate
> (/usr/bin/time -v):
>
> stats for https://github.com/apache/subversion/archive/1.9.12.tar.gz:
> Command being timed:
> "subversion-1.9.12/tools/server-side/svnauthz-validate acl.anon"
> User time (seconds): 0.02
> System time (seconds): 0.00
> Percent of CPU this job got: 80%
> Elapsed (wall clock) time (h:mm:ss or m:ss): *0:00.02*
> Maximum resident set size (kbytes): *7656*
> Minor (reclaiming a frame) page faults: *2812*
> Voluntary context switches: 32
> Involuntary context switches: 7
>
> stats for https://github.com/apache/subversion/archive/1.10.6.tar.gz:
> Command being timed:
> "subversion-1.10.6/tools/server-side/svnauthz-validate acl.anon"
> User time (seconds): 0.50
> System time (seconds): 0.02
> Percent of CPU this job got: 98%
> Elapsed (wall clock) time (h:mm:ss or m:ss): *0:00.53*
> Maximum resident set size (kbytes): *48704*
> Minor (reclaiming a frame) page faults: *13103*
> Voluntary context switches: 31
> Involuntary context switches: 9
>
> Last release still contains regression.
> stats for https://github.com/apache/subversion/archive/1.12.2.tar.gz
> Command being timed:
> "subversion-1.12.2/tools/server-side/svnauthz-validate acl.anon"
> User time (seconds): 0.48
> System time (seconds): 0.02
> Percent of CPU this job got: 98%
> Elapsed (wall clock) time (h:mm:ss or m:ss): *0:00.52*
> Maximum resident set size (kbytes): *49004*
> Minor (reclaiming a frame) page faults: *13095*
> Voluntary context switches: 32
> Involuntary context switches: 11
>
> Most of the time svnauthz-validate spends in the function svn_authz__parse
> (
> https://github.com/apache/subversion/blob/f91051c82d38a732b546a84f4ead491514e81010/subversion/libsvn_repos/authz_parse.c#L1369).
>
> It seems that in the tunnel mode redundantly parse all groups and all
> users - it should be done only for tunnel_user.
>
> Some host info:
> >> lsb_release -r
> Release: 16.04
> >> uname -a
> Linux host 4.4.171-70.1 #1 SMP Thu Jan 31 10:46:27 UTC 2019 x86_64 x86_64
> x86_64 GNU/Linux
> >> gcc --version
> gcc (Ubuntu 5.4.0-6ubuntu1~16.04.11) 5.4.0 20160609
>
> How subversion was built:
> >> ./autogen.sh
> >> ./configure
> >> make
>
> Thanks
>
Received on 2019-09-12 10:44:30 CEST