public inbox for systemtap@sourceware.org
 help / color / mirror / Atom feed
From: "Keshavamurthy, Anil S" <anil.s.keshavamurthy@intel.com>
To: <karim@opersys.com>, "Satoshi Oshima" <soshima@redhat.com>
Cc: "Richard J Moore" <richardj_moore@uk.ibm.com>,
	<systemtap@sources.redhat.com>, "Andi Kleen" <ak@suse.de>,
	"Mathieu Desnoyers" <compudj@krystal.dyndns.org>,
	"Masami Hiramatsu" <hiramatu@sdl.hitachi.co.jp>,
	"Masami Hiramatsu" <masami.hiramatsu@gmail.com>,
	<michel.dagenais@polymtl.ca>,
	"Roland McGrath" <roland@redhat.com>, <sugita@sdl.hitachi.co.jp>
Subject: RE: Hitachi djprobe mechanism
Date: Mon, 01 Aug 2005 20:46:00 -0000	[thread overview]
Message-ID: <44BDAFB888F59F408FAE3CC35AB4704101E98CFF@orsmsx409> (raw)


>In as far as I can see, it remains that the only safe way to 
>use djprobe
>is to not touch any instruction that is less than 5 bytes, that's if
>there aren't other limitations as I mentioned earlier.

Though this is the safe way to insert djprobe, this might not always
serve the desired purpose.

Say for example, user is interested to find how many times a function
gets called and he need 
to insert a probe at the beginning of a function. Due to the nature of
djprobe
1) we might not find a 5 byte instruction with in this function, Or
2) Even if we find one such instruction, that instruction might tend to 
not get executed (due to nature of the code flow), then in this case
If user inserts a probe looking at 5 bytes or more instruction from the
beginning 
of the function address, the results (i.e times a function entered) will
end up being wrong.

So in effect, we just can't look for instruction size greater than 5
bytes and insert probe there. 
This djprobe will push the need for a stronger static
analysizer/translator in selecting the probe point.

-thanks,
Anil



             reply	other threads:[~2005-08-01 20:46 UTC|newest]

Thread overview: 83+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-08-01 20:46 Keshavamurthy, Anil S [this message]
2005-08-01 21:08 ` Karim Yaghmour
  -- strict thread matches above, loose matches on Subject: below --
2005-08-01 22:49 Keshavamurthy, Anil S
2005-08-01 23:05 ` Karim Yaghmour
2005-08-01 23:18   ` Karim Yaghmour
2005-08-01 22:41 Keshavamurthy, Anil S
2005-08-02  3:21 ` Roland McGrath
2005-08-02  3:35   ` Karim Yaghmour
2005-08-01 16:14 Keshavamurthy, Anil S
2005-08-01 20:31 ` Roland McGrath
2005-08-04  0:28   ` Mathieu Desnoyers
2005-08-04 10:01     ` Andi Kleen
2005-08-05 16:25       ` Mathieu Desnoyers
2005-08-05 16:39         ` Andi Kleen
2005-08-01 15:50 Keshavamurthy, Anil S
2005-08-01 16:03 ` Mathieu Desnoyers
2005-07-29  0:18 Keshavamurthy, Anil S
2005-07-29  1:48 ` Karim Yaghmour
2005-07-29  3:41   ` Mathieu Desnoyers
2005-07-29  3:47     ` Karim Yaghmour
2005-07-29  1:53 ` Frank Ch. Eigler
2005-08-01  9:02   ` Mathieu Lacage
2005-08-01 13:18     ` Mathieu Desnoyers
2005-08-02  7:07       ` Mathieu Lacage
2005-07-27 21:05 Keshavamurthy, Anil S
2005-07-28  1:51 ` Karim Yaghmour
2005-07-28  2:10   ` Karim Yaghmour
2005-07-28 16:23     ` Masami Hiramatsu
2005-07-28 16:28       ` Karim Yaghmour
2005-07-28 17:36         ` Mathieu Desnoyers
     [not found]           ` <20050728110717.A30199@unix-os.sc.intel.com>
2005-07-28 18:33             ` Mathieu Desnoyers
     [not found]               ` <20050728133456.A32210@unix-os.sc.intel.com>
2005-07-28 23:53                 ` Richard J Moore
2005-07-29  5:59                 ` Mathieu Desnoyers
2005-07-29  7:55                   ` Andi Kleen
2005-07-29  8:44                     ` Richard J Moore
2005-07-29  8:46                       ` Andi Kleen
2005-07-29 15:51                     ` Mathieu Desnoyers
2005-07-30 15:55                       ` Andi Kleen
2005-07-30 16:54                         ` Mathieu Desnoyers
2005-07-31 22:03                           ` Andi Kleen
2005-07-31 23:11                             ` Mathieu Desnoyers
2005-08-01 15:37                               ` Andi Kleen
2005-08-01  8:44                             ` Richard J Moore
2005-08-01 13:21                               ` Mathieu Desnoyers
2005-08-01 19:57                               ` Satoshi Oshima
2005-08-01 20:21                                 ` Karim Yaghmour
2005-08-01 22:12                                   ` Satoshi Oshima
2005-08-01 22:54                                     ` Karim Yaghmour
2005-08-02 18:42                                       ` Satoshi Oshima
2005-08-03 14:50                                         ` Karim Yaghmour
2005-08-04  1:19                                         ` Mathieu Desnoyers
2005-08-04  3:31                                           ` Mathieu Desnoyers
2005-08-02  9:42                                   ` Mathieu Lacage
2005-08-02 15:09                                     ` Karim Yaghmour
2005-10-07 15:35                                     ` Richard J Moore
2005-10-08 18:33                                       ` mathieu lacage
2005-10-08 21:59                                         ` Richard J Moore
2005-10-08 23:24                                           ` Roland McGrath
2005-10-22 11:49                                             ` mathieu lacage
2005-10-22 22:09                                               ` Roland McGrath
2005-10-24  6:33                                                 ` Mathieu Lacage
2005-10-24 19:48                                                   ` Roland McGrath
     [not found]                                             ` <43621B0D.70204@sophia.inria.fr>
2005-11-07 10:04                                               ` mathieu lacage
2005-11-07 10:06                                                 ` mathieu lacage
2005-11-08  9:49                                             ` Richard J Moore
2005-10-09 16:47                                           ` mathieu lacage
2005-08-02 15:33                                   ` Mathieu Lacage
2005-08-02 15:36                                     ` Mathieu Lacage
2005-08-02 16:12                                     ` Karim Yaghmour
2005-08-02 16:30                                       ` Mathieu Lacage
2005-08-02 16:46                                         ` Karim Yaghmour
2005-08-04 17:09                                         ` Mathieu Lacage
2005-08-03 14:46                                 ` Andi Kleen
2005-07-29 16:06                   ` Frank Ch. Eigler
2005-07-29 18:24                     ` sugita
2005-07-28 18:13       ` Richard J Moore
2005-07-22 18:09 Frank Ch. Eigler
2005-07-21 22:32 Richard J Moore
2005-07-21 22:52 ` Roland McGrath
2005-07-22  2:52   ` Richard J Moore
2005-07-26  7:14   ` Masami Hiramatsu
2005-07-26  7:53     ` Roland McGrath
2005-07-27 13:02       ` Masami Hiramatsu

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=44BDAFB888F59F408FAE3CC35AB4704101E98CFF@orsmsx409 \
    --to=anil.s.keshavamurthy@intel.com \
    --cc=ak@suse.de \
    --cc=compudj@krystal.dyndns.org \
    --cc=hiramatu@sdl.hitachi.co.jp \
    --cc=karim@opersys.com \
    --cc=masami.hiramatsu@gmail.com \
    --cc=michel.dagenais@polymtl.ca \
    --cc=richardj_moore@uk.ibm.com \
    --cc=roland@redhat.com \
    --cc=soshima@redhat.com \
    --cc=sugita@sdl.hitachi.co.jp \
    --cc=systemtap@sources.redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).