Re: slapd's crypt usage is single threaded?

[Jesse Hathaway <jesse@mbuki-mvuki.org>]

On Fri, Feb 16, 2018 at 12:54 PM, Howard Chu <hyc@symas.com> wrote:
> Depends entirely on whether or not your libc supports crypt_r() (reentrant
> crypt). If not then yes, it has to be single-threaded because crypt() is not
> reentrant, it returns a pointer to static storage.
>
> And of course, even if you use crypt_r() it's always possible that the
> underlying cipher is itself single-threaded. We have no way to know and no
> control over that.

Thanks Chu for the followup, I made the mistake of looking at the master
source code which includes crypt_r support rather than the source code for
2.4.44 which we are presently running. It appears you added support for
crypt_r on Sep 6, 2017 with commit afa861bf22, however that commit does not
appear in any tagged version, `git tag --contains afa861bf22`

Do you have any idea when a version with this commit might be released?

I compiled master with crypt_r support and the results are much better

  $ pidstat -t -p $(pgrep slapd) 5 3
  <snip>
  Average:      UID      TGID       TID    %usr %system  %guest
%CPU   CPU  Command
  Average:      108     15720         -  788.67    0.07    0.00
788.73     -  slapd
  Average:      108         -     15720    0.00    0.00    0.00
0.00     -  |__slapd
  Average:      108         -     15721    0.00    0.00    0.00
0.00     -  |__slapd
  Average:      108         -     15722   98.40    0.00    0.00
98.40     -  |__slapd
  Average:      108         -     19581   38.80    0.00    0.00
38.80     -  |__slapd
  Average:      108         -     19585   94.40    0.00    0.00
94.40     -  |__slapd
  Average:      108         -     19591   94.00    0.00    0.00
94.00     -  |__slapd
  Average:      108         -     19592   65.27    0.00    0.00
65.27     -  |__slapd
  Average:      108         -     19650   98.80    0.00    0.00
98.80     -  |__slapd
  Average:      108         -     19754   97.93    0.00    0.00
97.93     -  |__slapd
  Average:      108         -      2526   39.00    0.00    0.00
39.00     -  |__slapd
  Average:      108         -      3293   98.67    0.00    0.00
98.67     -  |__slapd
  Average:      108         -      4694   63.60    0.00    0.00
63.60     -  |__slapd