[reiserfs-list] Re: [OpenAFS-devel] more on the 2.2.18pre17 SMP cpu hog/etc.

[Nathan Neulinger]

Checking the profile after unmounting afs and running afsd a second
time:

     4 startup_32                                 0.0244
     1 __switch_to                                0.0053
     2 system_call                                0.0357
     1 clear_page_tables                          0.0056
     1 find_vma                                   0.0100
     1 do_munmap                                  0.0018
     1 file_read_actor                            0.0125
     1 sys_writev                                 0.0057
     1 d_lookup                                   0.0045
     1 journal_mark_dirty                         0.0020
     1 n_tty_receive_buf                          0.0003
     1 __generic_copy_from_user                   0.0156
    16 total                                      0.0000

It doesn't seem to have any of those high-count calls.

-- Nathan

Andi Kleen wrote:
> 
> [you didn't say it in the mail, but I'll guess you're using a reiserfs
> partition as a afs cache]
> 
> On Fri, Dec 01, 2000 at 06:53:38PM -0600, Nathan Neulinger wrote:
> >
> > After the first time, it worked almost instantly. The first time through
> > though, this call in LINUX/osi_file.c
> >
> >         MYDEBUG("G");
> >     tip = iget(afs_cacheSBp, (u_long)ainode);
> >         MYDEBUG("H");
> >
> > that call takes TWELVE jiffies when it's slow. (Mydebug just prints out
> > a jiffies count with a label.)
> >
> > So, it seems to me that it might just be an issue with the particular
> > version of reiserfs or with the kernel. I'm running 3.5.25 on 2.2.17 at
> > work, 3.5.27 with 2.2.18pre17 at home. I do know that the filesystem at
> > work is using the tea hash, and at home is using r5 hash.
> >
> > (Reiserfs list: the files are named /afscache/V0 - /afscache/V99, there
> > are 102 files in the directory.)
> >
> > Any ideas?
> 
> Could you profile the kernel and see what is taking up the CPU ?
> (boot with profile=2 and read the profile log using readprofile afterwards)
> 
> -Andi

-- 


------------------------------------------------------------
Nathan Neulinger                       EMail:  nneul@umr.edu
University of Missouri - Rolla         Phone: (573) 341-4841
CIS - Systems Programming                Fax: (573) 341-4216