关于 cost constants 的校准

网上看到一篇@digoal写的文章，
http://blog.163.com/digoal@126/blog/static/163877040201310255717379/

打算在做这个设置，但是使用SystemTap 一直报错，请大神帮忙指点。

开始报错很多，我已经参考下面的文章 ，安装了跟我内核匹配的rpm包。
http://blog.163.com/digoal@126/blog/static/163877040201310113462317/

[root@localhost ~]# rpm -qa|grep coreutils
coreutils-debuginfo-8.4-19.el6.x86_64
coreutils-libs-8.4-19.el6.x86_64
coreutils-8.4-19.el6.x86_64
policycoreutils-2.0.83-19.30.el6.x86_64
[root@localhost ~]# rpm -qa|grep kernel-debuginfo
kernel-debuginfo-common-x86_64-2.6.32-573.18.1.el6.x86_64
kernel-debuginfo-2.6.32-573.18.1.el6.x86_64
[root@localhost ~]# uname -r
2.6.32-573.18.1.el6.x86_64

开启postgres：
-bash-4.1$ taskset -c 1 /usr/pgsql-9.2/bin/postgres >/dev/null 2>&1

进程号：
[root@localhost ~]# su - postgres
-bash-4.1$ psql
psql (9.2.14)
Type "help" for help.

postgres=# select pg_backend_pid();

pg_backend_pid

       2486

(1 row)

报错信息：

[root@localhost ~]# taskset -c 0 stap -e '

global a
probe process("/usr/pgsql-9.2/bin/postgres").mark("query__start") {
delete a
println("query__start ", user_string($arg1), "pid:", pid())
}
probe vfs.read.return {
t = gettimeofday_ns() - @entry(gettimeofday_ns())
# if (execname() == "postgres" && devname != "N/A")

a[pid()] <<< t

}
probe process("/usr/pgsql-9.2/bin/postgres").mark("query__done") {
if (@count(a[pid()]))

printdln("**", pid(), @count(a[pid()]), @avg(a[pid()]))

println("query__done ", user_string($arg1), "pid:", pid())
if (@count(a[pid()])) {

println(@hist_log(a[pid()]))
#println(@hist_linear(a[pid()],1024,4096,100))

}
delete a
}' -x 2486
semantic error: while resolving probe point: identifier 'process' at :3:7

    source: probe process("/usr/pgsql-9.2/bin/postgres").mark("query__start") {
                  ^

semantic error: no match

Pass 2: analysis failed. [man error::pass2]
Number of similar error messages suppressed: 1.
Rerun with -v to see them.