[M3devel] gettimeofday called from CheckLoadTracedRef?

[Jay]

It does appear to be making policy decisions based on elapsed time, not just collecting times to report.
 
Does gettimeofday on your system make a syscall or read a global?
 
 - Jay

Maybe since the intent is just to process one object/page, the CollectorOn/Off calls can be replaced by just
 collectorOn := TRUE or FALSE
 
 ? For CollectorOff that isn't clear since it does more, but CollectorOn is just that plus time recording plus an assertion. Still, given that the intent is some limited processing, I think the time collection could be avoided and might not even be a good thing?
 
 
 - Jay


----------------------------------------
> To: m3devel at elegosoft.com
> Date: Sat, 23 May 2009 13:34:16 -0700
> From: mika at async.caltech.edu
> CC: mika at camembert.async.caltech.edu
> Subject: [M3devel] gettimeofday called from CheckLoadTracedRef?
>
>
> Hi Modula-3ers, especially Tony,
>
> I'm seeing the following behavior a lot in a program I'm running:
>
> #0 0x68ecbba7 in gettimeofday () from /lib/libc.so.5
> #1 0x68611cb9 in Now () at ../src/time/POSIX/TimePosix.m3:16
> #2 0x685ecf06 in CollectorOn (timeOnEntry=Invalid C/C++ type code 30 in symbol table.
> ) at ../src/runtime/common/RTCollector.m3:674
> #3 0x685f2476 in CheckLoadTracedRef (ref=Invalid C/C++ type code 46 in symbol table.
> ) at ../src/runtime/common/RTCollector.m3:2271
> #4 0x68139379 in Get (tbl=Invalid C/C++ type code 26 in symbol table.
> )
> at ../FreeBSD4/SortedTotalOrderLRTbl.m3 => /usr/local/cm3/pkg/libm3/src/sortedtable/SortedTable.mg:145
>
> Is it normal for CheckLoadTracedRef to make system calls?
>
> Hmm, why is it even doing CheckLoadTracedRef? Here's the code (from SortedTable.mg):
>
>
> PROCEDURE Get ( tbl : Default;
> READONLY k : Key.T;
> VAR(*OUT*) v : Value.T): BOOLEAN =
> VAR
> x : Node := tbl.h.hi;
> cmp : Cmp;
> BEGIN
> WHILE (x # NIL) DO
> cmp := tbl.keyCompare (k, x.key);
> IF cmp = 0 THEN v := x.value; RETURN TRUE; END;
> IF (cmp < 0)
> THEN x := x.lo; (* line 145 *)
> ELSE x := x.hi;
> END;
> END;
> RETURN FALSE;
> END Get;
>
> where Node is defined as
>
> TYPE
> Node = REF RECORD
> key : Key.T;
> value : Value.T;
> lo : Node := NIL;
> hi : Node := NIL;
> priority: INTEGER (* random num; tree is a heap on these *)
> END;
>
> It seems odd to me that, under these circumstances, x := x.lo would
> cause any sort of checking activity...
>
> I'm using a CM3 that's about a month old, on FreeBSD4.
>
> Mika
>
> P.S. Needless to say, the code in question runs about 10x faster under
> PM3 than with this relatively new CM3... but my m3gdb is having trouble
> with PM3's LONGREALs for some reason.