[ I'm reposting this because Jeff's mail is still getting marked ] [ as spam by the Gna! mail server. -Chris ]
Date: Thu, 21 Dec 2006 08:25:53 -0500 From: Jeff Squyres <[EMAIL PROTECTED]> To: Chris Dunlap <[EMAIL PROTECTED]> cc: [email protected] Subject: Re: [munge-users] munged running at 100% On Dec 20, 2006, at 9:51 PM, Chris Dunlap wrote: > In the getgrent() loop in _gids_hash_create(), I replaced the call > to getpwnam() with _gids_user_to_uid() which caches the uid lookup in > a second hash. I was just curious to know how much of an effect the > uid caching had on very large passwd/group files, especially compared > to the 27min it took 0.5.6 based on the initial log. Ah! I missed that. I put some printf's around the gid hash map loop and ran munged in the foreground. 1. With skeletal passwd files (i.e., correct NIS configuration): 1a. the first loop took 12 seconds (with multiple runs, there was a pretty wide variance on this -- I saw times as high as 31 seconds, so I can only assume that this time is related to other factors, such as the present load on the NIS server). 1b. I then did "touch /etc/group" to force munged to reprocess the file. 1c. the next loop took about 12 seconds. 1d. I repeated the "touch /etc/group" step multiple times to see if the times would vary; they were consistently in the 11-13 second range. 2. With full passwd files (i.e., incorrect NIS configuration, so I'm not sure if this data point really matters): 2a. The first loop took 256 seconds 2b. As above, I executed "touch /etc/group" to for munged to reprocess the file. 2c. Subsequent times through the loop took ~250-260 seconds. I'm at a loss as to why the time is *significantly* shorter than it used to be, even for the *first* iteration through the loop. My own C test still takes ~600 seconds to getrent() across all entries. One issue could be time of day when I executed these tests: the tests in this mail were conducted between 7-8am US eastern time (4-5am US pacific time, where the NIS server is located). Tests in my prior e- mail were run about 12 hours difference from that (I don't remember the exact times, but it was late afternoon / early evening US eastern time), and loads on the NIS server could have been much different...? Regardless, the processing in munged itself got much faster, even if there's little difference between the first loop and subsequent loops. (I'm quite sure that this post won't reach the list; Gna! seems determined to classify my mail as junk :-( ) -- Jeff Squyres Server Virtualization Business Unit Cisco Systems _______________________________________________ munge-users mailing list [email protected] https://mail.gna.org/listinfo/munge-users
