On 14/05/2024 9:13 am, Leigh Brown wrote: > Although using integer comparison to compare doubles kind of > works, it's annoying to see domains slightly out of order when > sorting by cpu%. > > Add a compare_dbl() function and update compare_cpu_pct() to > call it. > > Signed-off-by: Leigh Brown <[email protected]> > --- > tools/xentop/xentop.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/tools/xentop/xentop.c b/tools/xentop/xentop.c > index 545bd5e96d..99199caec9 100644 > --- a/tools/xentop/xentop.c > +++ b/tools/xentop/xentop.c > @@ -85,6 +85,7 @@ static void set_delay(const char *value); > static void set_prompt(const char *new_prompt, void (*func)(const char *)); > static int handle_key(int); > static int compare(unsigned long long, unsigned long long); > +static int compare_dbl(double, double); > static int compare_domains(xenstat_domain **, xenstat_domain **); > static unsigned long long tot_net_bytes( xenstat_domain *, int); > static bool tot_vbd_reqs(xenstat_domain *, int, unsigned long long *); > @@ -422,6 +423,16 @@ static int compare(unsigned long long i1, unsigned long > long i2) > return 0; > } > > +/* Compares two double precision numbers, returning -1,0,1 for <,=,> */ > +static int compare_dbl(double d1, double d2) > +{ > + if(d1 < d2) > + return -1; > + if(d1 > d2) > + return 1; > + return 0; > +} > + > /* Comparison function for use with qsort. Compares two domains using the > * current sort field. */ > static int compare_domains(xenstat_domain **domain1, xenstat_domain > **domain2) > @@ -523,7 +534,7 @@ static double get_cpu_pct(xenstat_domain *domain) > > static int compare_cpu_pct(xenstat_domain *domain1, xenstat_domain *domain2) > { > - return -compare(get_cpu_pct(domain1), get_cpu_pct(domain2)); > + return -compare_dbl(get_cpu_pct(domain1), get_cpu_pct(domain2));
Oh, we were doing an implicit double->unsigned long long conversion. Over the range 0.0 to 100.0, that ought to work as expected. What kind of out-of-order are you seeing? Nevertheless, this should comparison should clearly be done using doubles. AFACT, get_cpu_pct() shouldn't ever return a NaN, so I think this simple form is fine. Oleksii: This is another bugfix to xentop, and should be considered for 4.19 at this point. ~Andrew
