Re: mysql static probes demo

[Mark Wielaard <mjw@redhat.com>]

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Hi Stan,

On Fri, 2009-01-23 at 15:29 -0500, Stan Cox wrote:
> Here is a demo of mysql being probed.

Wow, that is a really great demo!
What mysql source did you take and how did you configure/build it?

I did have some troubles with the new python wrapper to get postgres to
compile. I believe you should handle the creating of the output filename
differently when there has been no -o option given (and not add
extensions when it is given). I am attaching my local change.

Still trying to figure out how to actually enable the postgres probes
with the new runtime support though. All I am getting is:
        pattern '/usr/bin/postgres' matches module '/usr/bin/postgres'
        focused on module '/usr/bin/postgres = [0x8047000-0x841bb60,
        bias 0x0] file /usr/lib/debug/usr/bin/postgres.debug ELF machine
        i?86 (code 3)
        focused on module '/usr/bin/postgres'
        semantic error: no match while resolving probe point
        process("/usr/bin/postgres").statement(1869379436)
        dwarf_builder releasing user dwflpp /usr/bin/postgres
        semantic error: no probes found
Need to look into why.

Cheers,

Mark

[-- Attachment #2: dtrace.diff --]
[-- Type: text/x-patch, Size: 1277 bytes --]

diff --git a/dtrace b/dtrace
index 1eb53bf..fdf9da1 100755
--- a/dtrace
+++ b/dtrace
@@ -21,7 +21,7 @@ class provider:
         have_provider = False
         self.f = open(provider)
         self.h = open(header,mode='w')
-        self.h.write("// Generated by /usr/bin/dtrace\n")
+        self.h.write("// Generated by the Systemtap dtrace wrapper\n")
         self.h.write("\n#include <sys/sdt.h>\n\n")
         in_comment = False
         while (True):
@@ -125,21 +125,21 @@ if (build_header == False and build_source == False):
 if (filename == ""):
     if (s_filename != ""):
         filename = s_filename.replace(".d","")
+	if (build_header):
+	    filename = filename + ".h"
+	elif (build_source):
+	    filename = filename + ".o"
     else:
         usage
         sys.exit(1)
 
 if (build_header):
     providers = provider()
-    providers.open(s_filename, filename + ".h")
+    providers.open(s_filename, filename)
 elif (build_source):
     fn = "/tmp/" + os.path.basename(s_filename).replace(".d", ".c")
     f = open(fn,mode='w')
     f.write("static __dtrace () {}\n")
     f.close()
-    call("gcc -fPIC -c " + fn + " -o " + filename + ".o", shell=True)
-    f.close()
+    call("gcc -fPIC -c " + fn + " -o " + filename, shell=True)
     os.remove(fn)
-
-
-