[PATCH] xenmon: remove magic number "31" (the idle domain)

[PATCH] xenmon: remove magic number "31" (the idle domain)

[KUWAMURA Shin'ya]

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Hi,

This patch removes the magic number "31" for readability. The number
"31" means the idle domain ID.

In detail:
- display the idle domain ID with "Idle" instead of "31" 
- write to the file "log-idle.log" instead of "log-dom31.log".

Signed-off-by: KUWAMURA Shin'ya <kuwa@jp.fujitsu.com>

Thanks,
-- 
  KUWAMURA Shin'ya

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diff -r fd6d12935b56 tools/xenmon/xenmon.py
--- a/tools/xenmon/xenmon.py	Mon Jul  3 16:07:20 2006 +0100
+++ b/tools/xenmon/xenmon.py	Tue Jul  4 13:05:21 2006 +0900
@@ -36,6 +36,7 @@ import sys
 # constants
 NSAMPLES = 100
 NDOMAINS = 32
+IDLE_DOMAIN = 31 # idle domain's ID
 
 # the struct strings for qos_info
 ST_DOM_INFO = "6Q4i32s"
@@ -253,6 +254,14 @@ def display(scr, row, col, str, attr=0):
         sys.exit(1)
 
 
+# diplay domain id
+def display_domain_id(scr, row, col, dom):
+    if dom == IDLE_DOMAIN:
+        display(scr, row, col-1, "Idle")
+    else:
+        display(scr, row, col, "%d" % dom)
+
+
 # the live monitoring code
 def show_livestats(cpu):
     ncpu = 1         # number of cpu's on this platform
@@ -361,7 +370,7 @@ def show_livestats(cpu):
                 # display gotten
                 row += 1 
                 col = 2
-                display(stdscr, row, col, "%d" % dom)
+                display_domain_id(stdscr, row, col, dom)
                 col += 4
                 display(stdscr, row, col, "%s" % time_scale(h2[dom][0][0]))
                 col += 12
@@ -386,7 +395,7 @@ def show_livestats(cpu):
                 if options.allocated:
                     row += 1
                     col = 2
-                    display(stdscr, row, col, "%d" % dom)
+                    display_domain_id(stdscr, row, col, dom)
                     col += 28
                     display(stdscr, row, col, "%s/ex" % time_scale(h2[dom][1]))
                     col += 42
@@ -398,7 +407,7 @@ def show_livestats(cpu):
                 if options.blocked:
                     row += 1
                     col = 2
-                    display(stdscr, row, col, "%d" % dom)
+                    display_domain_id(stdscr, row, col, dom)
                     col += 4
                     display(stdscr, row, col, "%s" % time_scale(h2[dom][2][0]))
                     col += 12
@@ -418,7 +427,7 @@ def show_livestats(cpu):
                 if options.waited:
                     row += 1
                     col = 2
-                    display(stdscr, row, col, "%d" % dom)
+                    display_domain_id(stdscr, row, col, dom)
                     col += 4
                     display(stdscr, row, col, "%s" % time_scale(h2[dom][3][0]))
                     col += 12
@@ -438,7 +447,7 @@ def show_livestats(cpu):
                 if options.excount:
                     row += 1
                     col = 2
-                    display(stdscr, row, col, "%d" % dom)
+                    display_domain_id(stdscr, row, col, dom)
                     
                     col += 28
                     display(stdscr, row, col, "%d/s" % h2[dom][4])
@@ -451,7 +460,7 @@ def show_livestats(cpu):
                 if options.iocount:
                     row += 1
                     col = 2
-                    display(stdscr, row, col, "%d" % dom)
+                    display_domain_id(stdscr, row, col, dom)
                     col += 4
                     display(stdscr, row, col, "%d/s" % h2[dom][5][0])
                     col += 24
@@ -558,7 +567,10 @@ def writelog():
     curr = last = time.time()
     outfiles = {}
     for dom in range(0, NDOMAINS):
-        outfiles[dom] = Delayed("%s-dom%d.log" % (options.prefix, dom), 'w')
+        if dom == IDLE_DOMAIN:
+            outfiles[dom] = Delayed("%s-idle.log" % options.prefix, 'w')
+        else:
+            outfiles[dom] = Delayed("%s-dom%d.log" % (options.prefix, dom), 'w')
         outfiles[dom].delayed_write("# passed cpu dom cpu(tot) cpu(%) cpu/ex allocated/ex blocked(tot) blocked(%) blocked/io waited(tot) waited(%) waited/ex ex/s io(tot) io/ex\n")
 
     while options.duration == 0 or interval < (options.duration * 1000):

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Re: [PATCH] xenmon: remove magic number "31" (the idle domain)

[Keir Fraser]

On 4 Jul 2006, at 06:37, KUWAMURA Shin'ya wrote:

> This patch removes the magic number "31" for readability. The number
> "31" means the idle domain ID.
>
> In detail:
> - display the idle domain ID with "Idle" instead of "31"
> - write to the file "log-idle.log" instead of "log-dom31.log".
>
> Signed-off-by: KUWAMURA Shin'ya <kuwa@jp.fujitsu.com>

Where does the magic number '31' come from in the first place? That's 
not the number Xen uses. It could conflict with the domain id of a 
non-idle domain.

  -- Keir

Re: [PATCH] xenmon: remove magic number "31" (the idle domain)

[KUWAMURA Shin'ya]

Hi Keir,

>>>>> On Tue, 4 Jul 2006 08:06:57 +0100
>>>>> Keir.Fraser@cl.cam.ac.uk(Keir Fraser)  said:
> 
> 
> On 4 Jul 2006, at 06:37, KUWAMURA Shin'ya wrote:
> 
> > This patch removes the magic number "31" for readability. The number
> > "31" means the idle domain ID.
> 
> Where does the magic number '31' come from in the first place? That's 
> not the number Xen uses. It could conflict with the domain id of a 
> non-idle domain.

"31" comes from xenmon.py and xenbaked.h.
xenmon.py:38:
  NDOMAINS = 32

xenbaked.h:42
  #define NDOMAINS 32

Notice that 31 is NDOMAINS-1.

Therefore, xenmon supports only up to 32 domains.

Thanks,
-- 
  KUWAMURA Shin'ya

Re: [PATCH] xenmon: remove magic number "31" (the idle domain)

[Keir Fraser]

On 4 Jul 2006, at 08:48, KUWAMURA Shin'ya wrote:

>> Where does the magic number '31' come from in the first place? That's
>> not the number Xen uses. It could conflict with the domain id of a
>> non-idle domain.
>
> "31" comes from xenmon.py and xenbaked.h.
> xenmon.py:38:
>   NDOMAINS = 32
>
> xenbaked.h:42
>   #define NDOMAINS 32
>
> Notice that 31 is NDOMAINS-1.
>
> Therefore, xenmon supports only up to 32 domains.

That's poor, since it in fact only really supports the first 31 domains 
created on a system (domain ids don't necessarily quickly get reused; 
and 32nd domid is used as sentinel to indicate idle). It shouldn't be 
hard to use a data structure more complicated than (presumably) a small 
array indexed by domid.

  -- Keir

Re: [PATCH] xenmon: remove magic number "31" (the idle domain)

[Rob Gardner]

Keir Fraser wrote:
>> Therefore, xenmon supports only up to 32 domains.
>
> That's poor, since it in fact only really supports the first 31 
> domains created on a system (domain ids don't necessarily quickly get 
> reused; and 32nd domid is used as sentinel to indicate idle). It 
> shouldn't be hard to use a data structure more complicated than 
> (presumably) a small array indexed by domid. 

I know about this problem. I've got a fix for it I prepared some time 
ago but never got around to submitting. I'll integrate it with the 
latest source and get it sent out this week.

Rob