From: Li Guanglei <guanglei@cn.ibm.com>
To: William Cohen <wcohen@redhat.com>
Cc: "systemtap@sourceware.org" <systemtap@sourceware.org>
Subject: Re: [UPDATE] Linux Kernel Event Trace tool(LKET)
Date: Thu, 25 May 2006 08:23:00 -0000 [thread overview]
Message-ID: <44756975.8020408@cn.ibm.com> (raw)
In-Reply-To: <44747B35.8070907@redhat.com>
William Cohen ??:
>
> I read through the LKET manpage this morning and tried out LKET with
> providing ASCII output on a 32-bit i686 FC5 machine and a 64-bit x86_64
> FC5 machine.
> [...]
>
> It looks like there are some portability issues that need to be worked
> out in the code. Things seemed to work better on the 64-bit platform
> than on the 32-bit platform.
Today I used my thinkpad install with FC5/2.6.16.13, and found the
same problems as you mentioned.
This is because that _stp_vsnprintf use va_arg() to get arguments and
some arguments have wrong type in 32-bit applications. I fixed this in
all current LKET tapsets and checked them into CVS.
I did a testing for all event hooks in ppc64/2.6.16.5 & i386/2.6.16.13
for both ascii tracing(-D ASCII_TRACE) and binary tracing(with -bM and
later use runtime/lket/b2a/lket-b2a to convert into ascii format), and
most of the problems have gone, except the _switch_to & idle_balance
which will be explained below.
>
> The tskdispatch didn't work on either machine. Couldn't find
> kernel.function("__switch_to") on 64-bit and couldn't find
> kernel.inline("idle_balance") on 32-bit
I don't have a x86_64 at hand. I tried __switch_to(scheduler.ctxswitch
in src/tapset/schedule.stp) and it will cause kernel panic. I will
take a further look at this and will open a bug for this if needed.
idle_balance is only available on SMP boxes. On single-cpu box, it
will be commented out. I will try to find other replacements of
idle_balance.
>
> Neither machine has scsi interface. When trying out the flagged errors
> because no scsi modules.
I tested on my thinkpad since it has scsi device(SATA) and it works well.
>
> $ stap -D ASCII_TRACE -e "probe addevent.pagefault {}" -I
> /usr/local/share/systemtap/tapset/LKET/
>
>
> The data on the 32-bit machine looked bogus (see below). lots of
> negative references. Also would it make more sens to have the address
> printed in hexidecimal for the ascii trace?
>
> 6|1|0|1148483972|626999|1848|1|1848|35705849838043136|1
> 6|1|0|1148483972|627050|1848|1|1848|-4615772671219597312|1
> 6|1|0|1148483974|465231|1324|1|1324|-5191788353242005504|1
>
For ascii tracing, I printed the pointer in %d, so this is why you see
negtive values.
>
> $ stap -D ASCII_TRACE -e "probe addevent.netdev.* {}" -I
> /usr/local/share/systemtap/tapset/LKET/
>
> The netdev worked on 64-bit, but it failed compilation on 32-bit:
>
> cc1: warnings being treated as errors
> /tmp/stapBs84Hc/stap_15261.c: In function 'function_log_netdev_extra':
> /tmp/stapBs84Hc/stap_15261.c:434: warning: cast to pointer from integer
> of different size
I've fixed this in CVS
>
> -Will
>
next prev parent reply other threads:[~2006-05-25 8:23 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-05-12 22:34 Stone, Joshua I
2006-05-15 6:34 ` Li Guanglei
2006-05-19 4:09 ` Li Guanglei
2006-05-23 23:33 ` Li Guanglei
2006-05-24 15:27 ` William Cohen
2006-05-25 0:21 ` Li Guanglei
2006-05-27 2:35 ` Guang Lei Li
2006-05-25 8:23 ` Li Guanglei [this message]
2006-05-29 6:26 ` Li Guanglei
2006-05-24 15:43 ` Frank Ch. Eigler
2006-05-25 14:03 ` Li Guanglei
-- strict thread matches above, loose matches on Subject: below --
2006-06-02 0:48 Stone, Joshua I
2006-06-02 1:56 ` Li Guanglei
2006-06-02 0:44 Stone, Joshua I
2006-05-15 21:09 Stone, Joshua I
2006-05-11 8:26 Li Guanglei
[not found] ` <446A2BB6.4040700@lanl.gov>
2006-05-17 0:18 ` Li Guanglei
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