# Benchmark segfault \] **URL:** \ **Category:** Ruby\ **Created:** [June 12, 2007, 11:52am UTC](https://www.ruby-forum.com/t/benchmark-segfault/106607 "2007-06-12T11:52:27Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Michal\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/779978/32.png) [@Michal\_S](https://www.ruby-forum.com/u/Michal_S)\ **Post date:** [June 12, 2007, 11:52am UTC](https://www.ruby-forum.com/t/benchmark-segfault/106607/1 "2007-06-12T11:52:27Z")
On 11/06/07, Robert K. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > Benchmark::bmbm do |x| > > two-bang 1604.816667 1.350000 1606.166667 (963.803356) > > x.report(“zip”) { Hash[\*id\_list.zip(id\_list.collect {|e| e.object\_id})] } > > GC. You’ll probably see much different results if your input array is > > much shorter (try with 10 or 100 elements). I also get a segfault (with 1.8.5 on Gentoo): ruby -w test.rb Rehearsal -------------------------------------------- inject 7.210000 0.870000 8.080000 ( 13.011414) non-bang 4620.790000 179.730000 4800.520000 (6029.976497) bang 4586.140000 200.530000 4786.670000 (5970.267190) two-bang 4599.560000 268.080000 4867.640000 (6035.687979) ------------------------------- total: 14462.910000sec ``` user system total real ``` inject 10.740000 1.990000 12.730000 ( 15.500874) non-bang Segmentation fault hramrach@hp-tc2110:11(0) 06120053 16]~ $ ruby -v ruby 1.8.5 (2006-12-04 patchlevel 2) [i686-linux] Of course, it would be better to test with 1.8.6 but it takes quite some time to retest 😉 Thanks Michal ---
**Author:** ![Michal\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/779978/32.png) [@Michal\_S](https://www.ruby-forum.com/u/Michal_S)\ **Post date:** [June 12, 2007, 1:15pm UTC](https://www.ruby-forum.com/t/benchmark-segfault/106607/2 "2007-06-12T13:15:41Z")
On 12.06.2007 11:52, Michal S. wrote: > > > Hash[\*id\_list.collect { |e| [e,e.object\_id]}.flatten] > > > id\_list = (1…1\_000\_000).to\_a > > non-bang Segmentation fault > hramrach@hp-tc2110:11(0) 06120053 16]~ $ ruby -v > ruby 1.8.5 (2006-12-04 patchlevel 2) [i686-linux] > > Of course, it would be better to test with 1.8.6 but it takes quite > some time to retest 😉 > > Thanks > > Michal I believe it’s the star operator: 13:10:22 [Temp]: ruby -e ‘Hash[\*Array.new(ARGV.shift.to\_i)]’ 1000000 13:10:35 [Temp]: ruby -e ‘Hash[\*Array.new(ARGV.shift.to\_i)]’ 10000000 -e:1: [BUG] Segmentation fault ruby 1.8.6 (2007-03-13) [i386-cygwin] Aborted (core dumped) 13:10:39 [Temp]: ruby -e ‘def f(\*a) end; f(\*Array.new(ARGV.shift.to\_i))’ 1000000 13:11:09 [Temp]: ruby -e ‘def f(\*a) end; f(\*Array.new(ARGV.shift.to\_i))’ 10000000 -e:1: [BUG] Segmentation fault ruby 1.8.6 (2007-03-13) [i386-cygwin] Aborted (core dumped) 13:11:14 [Temp]: uname -a CYGWIN\_NT-5.2-WOW64 PDBXPWSRK38 1.5.24(0.156/4/2) 2007-01-31 10:57 i686 Cygwin 13:11:36 [Temp]: ruby --version ruby 1.8.6 (2007-03-13 patchlevel 0) [i386-cygwin] Kind regards robert ---
**Author:** ![Michal\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/779978/32.png) [@Michal\_S](https://www.ruby-forum.com/u/Michal_S)\ **Post date:** [June 12, 2007, 4:25pm UTC](https://www.ruby-forum.com/t/benchmark-segfault/106607/3 "2007-06-12T16:25:38Z")
On 12.06.2007 16:16, Florian F. wrote: > > 1000000 > > ruby 1.8.6 (2007-03-13 patchlevel 0) [i386-cygwin] > > The reason for this problem is, that the stack is used to pass A LOT of > arguments to the Hash.[] method. If the stack size of the executed process isn’t > big enough (check your resource limits), this can lead to crashes. That was what I was guessing. However, I haven’t enough insight to verify. There is at least one point that causes me doubt: the array can be handled and stored like any other array, so it should be on the heap (or it is implicitly moved there). Kind regards robert ---
**Author:** ![Michal\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/779978/32.png) [@Michal\_S](https://www.ruby-forum.com/u/Michal_S)\ **Post date:** [June 12, 2007, 4:40pm UTC](https://www.ruby-forum.com/t/benchmark-segfault/106607/4 "2007-06-12T16:40:40Z")
On Tue, Jun 12, 2007 at 11:25:04PM +0900, Robert K. wrote: > On 12.06.2007 16:16, Florian F. wrote: > > > Robert K. wrote: > > > > > I believe it’s the star operator: > > > > > > 13:10:22 [Temp]: ruby -e ‘Hash[\*Array.new(ARGV.shift.to\_i)]’ 1000000 > > > 13:10:35 [Temp]: ruby -e ‘Hash[\*Array.new(ARGV.shift.to\_i)]’ 10000000 > > > -e:1: [BUG] Segmentation fault > > > ruby 1.8.6 (2007-03-13) [i386-cygwin] > > > […] > > > The reason for this problem is, that the stack is used to pass A LOT of > > arguments to the Hash.[] method. If the stack size of the executed process > > isn’t > > big enough (check your resource limits), this can lead to crashes. > > That was what I was guessing. However, I haven’t enough insight to > verify. There is at least one point that causes me doubt: the array can > be handled and stored like any other array, so it should be on the heap > (or it is implicitly moved there). $ ruby -e ‘Hash[\*Array.new(ARGV.shift.to\_i)]’ 2091000 -e:1:in `[]': stack level too deep (SystemStackError) from -e:1 $ ruby -e 'Hash[*Array.new(ARGV.shift.to_i)]' 2092000 Segmentation fault $ ulimit -s 8192 $ ulimit -s 16384 $ ruby -e 'Hash[*Array.new(ARGV.shift.to_i)]' 2092000 $ ruby -e 'Hash[*Array.new(ARGV.shift.to_i)]' 4184000 -e:1:in`[]’: stack level too deep (SystemStackError) from -e:1 $ ruby -e ‘Hash[\*Array.new(ARGV.shift.to\_i)]’ 4190000 Segmentation fault ---
**Author:** ![Michal\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/779978/32.png) [@Michal\_S](https://www.ruby-forum.com/u/Michal_S)\ **Post date:** [June 12, 2007, 4:17pm UTC](https://www.ruby-forum.com/t/benchmark-segfault/106607/5 "2007-06-12T16:17:37Z")
Robert K. wrote: > 13:11:09 [Temp]: ruby -e ‘def f(\*a) end; f(\*Array.new(ARGV.shift.to\_i))’ > 10000000 > -e:1: [BUG] Segmentation fault > ruby 1.8.6 (2007-03-13) [i386-cygwin] > > Aborted (core dumped) > 13:11:14 [Temp]: uname -a > CYGWIN\_NT-5.2-WOW64 PDBXPWSRK38 1.5.24(0.156/4/2) 2007-01-31 10:57 i686 > Cygwin > 13:11:36 [Temp]: ruby --version > ruby 1.8.6 (2007-03-13 patchlevel 0) [i386-cygwin] The reason for this problem is, that the stack is used to pass A LOT of arguments to the Hash.[] method. If the stack size of the executed process isn’t big enough (check your resource limits), this can lead to crashes. ---
**Author:** ![Michal\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/779978/32.png) [@Michal\_S](https://www.ruby-forum.com/u/Michal_S)\ **Post date:** [June 13, 2007, 6:41am UTC](https://www.ruby-forum.com/t/benchmark-segfault/106607/6 "2007-06-13T06:41:16Z")
Hi, At Wed, 13 Jun 2007 00:50:30 +0900, Florian F. wrote in [ruby-talk:255348]: > Yes, the implementation of this is in eval.c’s rb\_call0, after that the > arguments are passed along via the argc/argv function arguments. Ruby also tries > to throw a SystemStackError in rb\_call0 like Mauricio has shown, but this isn’t > guaranteed to work in all cases. Actually, the definition of TMP\_ALLOC. Try replacing #ifdef C\_ALLOCA with #if 1. ---
**Author:** ![Michal\_S](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/779978/32.png) [@Michal\_S](https://www.ruby-forum.com/u/Michal_S)\ **Post date:** [June 12, 2007, 5:52pm UTC](https://www.ruby-forum.com/t/benchmark-segfault/106607/7 "2007-06-12T17:52:04Z")
Robert K. wrote: > That was what I was guessing. However, I haven’t enough insight to > verify. There is at least one point that causes me doubt: the array can > be handled and stored like any other array, so it should be on the heap > (or it is implicitly moved there). Yes, the implementation of this is in eval.c’s rb\_call0, after that the arguments are passed along via the argc/argv function arguments. Ruby also tries to throw a SystemStackError in rb\_call0 like Mauricio has shown, but this isn’t guaranteed to work in all cases.