Date: Thu, 5 Feb 2009 11:31:52 -0500 From: Klapper Zhu <klapperzhu@gmail.com> To: freebsd-current@freebsd.org Subject: To John Birrell: weird behaviors of DTrace on amd64 Message-ID: <a29c138b0902050831q13844f7bm3aa3bdebdcb9733e@mail.gmail.com>
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Hi John Birrell,
I am exploring DTrace on "7.1-STABLE FreeBSD amd64" and I found several
weird behaviors:
1) Not all kernel functions show up in fbt provider. Take isp(4) as example:
"dtrace -l" shows
static void isp_freeze_loopdown(ispsoftc_t *, int, char *);
___but not___
static void isp_handle_platform_atio2(ispsoftc_t *, at2_entry_t *);
Both are static functions. But one shows up in fbt, another not.
What's the rational behind it ? Any way to fix it ?
2) The symptom described below only shows in 64-bit platform (amd64).
Here is the D Code:
fbt::isp_handle_platform_atio2:entry
{
self->cdb =args[1]->at_cmnd.cdb_dl.sf.fcp_cmnd_cdb[0];
printf("%s(%x, %x, cdb_cmd %x)\n", probefunc, arg0, arg1, self->cdb);
}
It will never fire.
I have to add another 2 probes on top of it, then it
(fbt::isp_handle_platform_atio2:entry) will trace.
Even the 2 probes on top of it never fire.
---------------
dtrace:::BEGIN
{
tr = 0;
}
fbt:::entry
/tr == 1/
{
@a[probefunc] = count();
}
fbt::isp_handle_platform_atio2:entry
{
self->cdb =args[1]->at_cmnd.cdb_dl.sf.fcp_cmnd_cdb[0];
printf("%s(%x, %x, cdb_cmd %x)\n", probefunc, arg0, arg1, self->cdb);
}
Thanks,
Z. Zhu
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