Hello,
On 2024-05-14 13:07, Andrew Cooper wrote:
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?
Without patch:
xentop - 13:29:01 Xen 4.18.2
13 domains: 1 running, 12 blocked, 0 paused, 0 crashed, 0 dying, 0
shutdown
Mem: 67030640k total, 33097800k used, 33932840k free CPUs: 24 @
3693MHz
NAME STATE CPU(sec) CPU(%) MEM(k) MEM(%) MAXMEM(k)
MAXMEM(%)
icecream --b--- 2597 6.6 4194368 6.3 4195328
6.3
xendd --b--- 4016 5.4 524268 0.8 525312
0.8
Domain-0 -----r 1059 1.7 1048576 1.6 1048576
1.6
neon --b--- 826 1.1 2097216 3.1 2098176
3.1
blender --b--- 121 0.2 1048640 1.6 1049600
1.6
bread --b--- 69 0.1 524352 0.8 525312
0.8
bob --b--- 502 0.3 16777284 25.0 16778240
25.0
cheese --b--- 225 0.5 1048384 1.6 1049600
1.6
cassini --b--- 489 0.4 3145792 4.7 3146752
4.7
chickpea --b--- 67 0.1 524352 0.8 525312
0.8
lentil --b--- 67 0.1 262208 0.4 263168
0.4
fusilli --b--- 159 0.2 524352 0.8 525312
0.8
pizza --b--- 359 0.5 524352 0.8 525312
0.8
With patch:
xentop - 13:30:17 Xen 4.18.2
13 domains: 1 running, 12 blocked, 0 paused, 0 crashed, 0 dying, 0
shutdown
Mem: 67030640k total, 33097788k used, 33932852k free CPUs: 24 @
3693MHz
NAME STATE CPU(sec) CPU(%) MEM(k) MEM(%) MAXMEM(k)
MAXMEM(%)
xendd --b--- 4020 5.7 524268 0.8 525312
0.8
icecream --b--- 2600 3.8 4194368 6.3 4195328
6.3
Domain-0 -----r 1060 1.5 1048576 1.6 1048576
1.6
neon --b--- 827 1.1 2097216 3.1 2098176
3.1
cheese --b--- 225 0.7 1048384 1.6 1049600
1.6
pizza --b--- 359 0.5 524352 0.8 525312
0.8
cassini --b--- 490 0.4 3145792 4.7 3146752
4.7
fusilli --b--- 159 0.2 524352 0.8 525312
0.8
bob --b--- 502 0.2 16777284 25.0 16778240
25.0
blender --b--- 121 0.2 1048640 1.6 1049600
1.6
bread --b--- 69 0.1 524352 0.8 525312
0.8
chickpea --b--- 67 0.1 524352 0.8 525312
0.8
lentil --b--- 67 0.1 262208 0.4 263168
0.4
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
Regards,
Leigh.
