Re: perf MMAP2 interface and COW faults

2014-03-17 Thread Peter Zijlstra
On Mon, Mar 17, 2014 at 11:37:47AM -0400, Don Zickus wrote: > Yes this seemed to work. I attached a slight update to your patch (one > that compiles :-) ). And I will reply to this thread with the tool > changes I used to verify this (in case I did that piece wrong). :-) OK, I'll write it a cha

Re: perf MMAP2 interface and COW faults

2014-03-17 Thread Don Zickus
On Mon, Mar 17, 2014 at 11:37:47AM -0400, Don Zickus wrote: > On Fri, Mar 14, 2014 at 12:17:05PM +0100, Peter Zijlstra wrote: > > On Thu, Mar 13, 2014 at 04:03:52PM -0400, Don Zickus wrote: > > > Hi Peter, > > > > > > So we found another corner case with MMAP2 interface. I don't think it is > > >

Re: perf MMAP2 interface and COW faults

2014-03-17 Thread Don Zickus
On Fri, Mar 14, 2014 at 12:17:05PM +0100, Peter Zijlstra wrote: > On Thu, Mar 13, 2014 at 04:03:52PM -0400, Don Zickus wrote: > > Hi Peter, > > > > So we found another corner case with MMAP2 interface. I don't think it is > > a big hurdle to overcome, just wanted a suggestion. > > > > Joe ran sp

Re: perf MMAP2 interface and COW faults

2014-03-14 Thread Don Zickus
On Fri, Mar 14, 2014 at 02:24:47PM +0100, Peter Zijlstra wrote: > On Fri, Mar 14, 2014 at 08:58:37AM -0400, Don Zickus wrote: > > Hmmm. That will probably work for future mmap events. My problem is for > > synthesized mmap events. We read the same protection bits from > > /proc//maps file, so I

Re: perf MMAP2 interface and COW faults

2014-03-14 Thread Peter Zijlstra
On Fri, Mar 14, 2014 at 08:58:37AM -0400, Don Zickus wrote: > Hmmm. That will probably work for future mmap events. My problem is for > synthesized mmap events. We read the same protection bits from > /proc//maps file, so I assume the same strategy can work for those > events too? Yeah, so /pro

Re: perf MMAP2 interface and COW faults

2014-03-14 Thread Don Zickus
On Fri, Mar 14, 2014 at 12:17:05PM +0100, Peter Zijlstra wrote: > On Thu, Mar 13, 2014 at 04:03:52PM -0400, Don Zickus wrote: > > Hi Peter, > > > > So we found another corner case with MMAP2 interface. I don't think it is > > a big hurdle to overcome, just wanted a suggestion. > > > > Joe ran sp

Re: perf MMAP2 interface and COW faults

2014-03-14 Thread Peter Zijlstra
On Thu, Mar 13, 2014 at 04:03:52PM -0400, Don Zickus wrote: > Hi Peter, > > So we found another corner case with MMAP2 interface. I don't think it is > a big hurdle to overcome, just wanted a suggestion. > > Joe ran specjbb2013 (which creates about 10,000 java threads across 9 > processes) and o

perf MMAP2 interface and COW faults

2014-03-13 Thread Don Zickus
Hi Peter, So we found another corner case with MMAP2 interface. I don't think it is a big hurdle to overcome, just wanted a suggestion. Joe ran specjbb2013 (which creates about 10,000 java threads across 9 processes) and our c2c tool turned up some cacheline collision data on libjvm.so. This di