Quoting Larry Bassel (2015-02-24 13:50:51)
> On 24 Feb 15 21:53, Vincent Guittot wrote:
> > On 8 February 2015 at 01:08, Larry Bassel <larry.bas...@linaro.org> wrote:
> > > +check_sched_domain_flags() {
> > > +
> > > + cpu_num=$1
> > > + domain_num=$2
> > > +
> > > +
> > > sched_domain_flags=/proc/sys/kernel/sched_domain/$cpu_num/domain$domain_num/flags
> > > + val=$(cat $sched_domain_flags)
> > > +
> > > + check "sched_domain_flags (domain $domain_num)" "test \"$val\" !=
> > > \"-1\""
> > > + printf "domain$domain_num flag 0x%x\n" $val
> > > +
> > > + is_flag_set $val 0x80 "domain$domain_num share cpu capacity flag"
> > > + is_flag_set $val 0x100 "domain$domain_num share power domain flag"
> > > + is_flag_set $val 0x200 "domain$domain_num share cpu package
> > > resources flag"
> >
> > could you use a list of masks to be tested against $val instead of
> > hard coding them ? the number of flags to be tested should increase
> > with eas patchset
> >
>
> Yes, this is a good idea. What is the best (i.e. cleanest/most
> maintainable/most portable) way of doing this in a shell script?
SD flags are not exported to userspace so we can't scrape them at
run-time from /usr/include/linux/sched.h. That would be the most
future-proof way of doing it, but would require packaging kernel
headers, etc.
> Arrays of masks and corresponding strings? I think I remember
> Lisa telling me that arrays aren't portable as they are not in
> all shells.
The current implementation isn't very future-proof. If the definition of
a flag is missing from the script then it is silently ignored. A better
way is to iterate over every bit in the 32-bit flag mask and print out
whether that bit is set or unset, and also a human-friendly definition
if that is known. But not having the human-readable definition should
not exclude the numeric value from being displayed since we might create
new flags as Vincent suggested.
More realistically it looks like all of the current flags fit in the
bottom 16 bits of the flag mask, so maybe we can just print the first 16
bits instead of 32. Maybe something like:
for i in $(seq 16); do is_flag_set $val $i; done
Where is_flag_set prints whether bit $i is set or unset in $val.
is_flag_set can also maintain the table/array of human-readable flags
for well-defined definitions that we consider to be stable/unchanging.
Regards,
Mike
>
> Thanks.
>
> Larry
>
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