[dtrace-discuss] [Fwd: [zfs-discuss] DTrace IO provider and oracle]

[przemolicc at poczta.fm]

Hello,

I have sent the following e-mail by mistake to zfs-discuss. Anyway Tao Chen answered my question.
But I would like to ask a more general question: since oracle uses its database files by
mmap (am I right ?) how can I (d)trace io activity to mmap-ed files ? According to
http://docs.sun.com/app/docs/doc/817-0404/6mg74vs9i?a=view
fsflush is the proces which flushes dirty pages to disk. Is fsflush the only one system process
which "touches" mmap-ed files ?

przemol

----- Forwarded message from przemolicc at poczta.fm -----

> From: przemolicc at poczta.fm
> To: zfs-discuss at opensolaris.org
> Subject: [zfs-discuss] DTrace IO provider and oracle
> Date: Tue, 8 Aug 2006 15:54:26 +0200
> 
> Hello,
> 
> Solaris 10 GA + latest recommended patches:
> 
> while runing dtrace:
> 
> bash-3.00# dtrace -n 'io:::start {@[execname, args[2]->fi_pathname] = count();}'
> ...
>   vim                                                 /zones/obsdb3/root/opt/sfw/bin/vim                              296
>   tnslsnr                                             <none>                                                         2373
>   fsflush                                             <none>                                                         2952
>   sched                                               <none>                                                         9949
>   ar60run                                             <none>                                                        13590
>   RACUST                                              <none>                                                        39252
>   RAXTRX                                              <none>                                                        39789
>   RAXMTR                                              <none>                                                        40671
>   FNDLIBR                                             <none>                                                        64956
>   oracle                                              <none>                                                      2096052
> 
> How can I interpret '<none>' ? Is it possible to get full path (like in vim) ?

Section "27.2.3 fileinfo_t" of DTrace Guide
explains in detail why you see '<none>' in many cases.
http://www.sun.com/bigadmin/content/dtrace/d10_latest.pdf
or
http://docs.sun.com/app/docs/doc/817-6223/6mlkidllf?a=view

The "execname" part can also be misleading, as many I/O activities are
"asynchronous" (including but not limited to Asynchronous I/O), so whatever
thread running on CPU may have nothing to do with the I/O that's occuring.

This is working as designed and not a "problem" that limited to ZFS, IMO.

Tao


> 
> Regards
> przemol
> _______________________________________________
> zfs-discuss mailing list
> zfs-discuss at opensolaris.org
> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss

----- End forwarded message -----