[Tcl-bugs] [ tcl-Bugs-1586292 ] threaded build too slow?

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Bugs item #1586292, was opened at 2006-10-28 13:00
Message generated for change (Comment added) made by msofer
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Category: 48. Threading
Group: development: 8.5a6
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: miguel sofer (msofer)
Assigned to: miguel sofer (msofer)
Summary: threaded build too slow?

Initial Comment:
For reasons that are not important here, I timed the
speed of proc and ensemble calls in current HEAD. The
threaded build is *much* slower (1.75x). 

The script at /tmp/test is

   proc a {x y} {set x 1}
   namespace ensemble create -command ::w -map {a a}
   # Just to make the timings stabilise accross runs
   # ... probably too much, but who cares
   time {a 1 2} 10000
   time {w a 1 2} 10000
   lappend res proc:[time {a 1 2} 10000]
   lappend res ense:[time {w a 1 2} 10000]
   lappend res [info patchlevel]
   puts [join $res \n]

Building with --disable-shared I get

   sh-3.1# ./tclsh /tmp/test
   proc:2.3583 microseconds per iteration
   ense:3.1632 microseconds per iteration
   8.5a6

and with --disable-shared --enable-threads

   sh-3.1# ./tclsh /tmp/test
   proc:4.1325 microseconds per iteration
   ense:5.8033 microseconds per iteration
   8.5a6


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>Comment By: miguel sofer (msofer)
Date: 2006-10-28 14:08

Message:
Logged In: YES 
user_id=148712

Disabling the call to TclpCheckStackSpace in TclInterpReady
makes threaded builds quite a bit faster:

mig@ice:/home/CVS/tcl_SF_clean/unix$ ./tclsh /tmp/test
proc:3.0335 microseconds per iteration
ense:4.5398 microseconds per iteration
8.5a6


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Comment By: miguel sofer (msofer)
Date: 2006-10-28 14:01

Message:
Logged In: YES 
user_id=148712

Threaded build using glibc's malloc instead of Tcl's pooled
allocator it is even slower, so the problem is probably not
mainly with the allocator.

mig@ice:/home/CVS/tcl_SF_clean/unix$ ./tclsh /tmp/test
proc:4.4455 microseconds per iteration
ense:6.0062 microseconds per iteration
8.5a6


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Comment By: miguel sofer (msofer)
Date: 2006-10-28 13:21

Message:
Logged In: YES 
user_id=148712

With ActiveTcl it is even slower (I imagine this is due to
the shared build, as not much optimisation has been done in
proc calls since then):
mig@ice:/home/CVS/tcl_SF_clean/unix$ tclsh /tmp/test
proc:5.4506 microseconds per iteration
ense:7.678 microseconds per iteration
8.5a4

% parray ::activestate::ActiveTcl
::activestate::ActiveTcl(arch)          = linux-ix86
::activestate::ActiveTcl(as,mode)       = normal
::activestate::ActiveTcl(build)         = 261540
::activestate::ActiveTcl(buildtime,fmt) = Sat Apr 15
01:24:58 AM PDT 2006
::activestate::ActiveTcl(buildtime,sec) = 1145089498
::activestate::ActiveTcl(maturity)      = beta-5
::activestate::ActiveTcl(product)       = ActiveTcl
::activestate::ActiveTcl(release)       = 8.5.0.0


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