Re: svn commit: r254380 - in head/sys: kern sys

2013-08-16 Thread Colin Percival
On 08/16/13 02:38, Ivan Voras wrote: >> We have a single-writer / multiple-readers lock on *any particular byte* >> of a vnode. The rangelock code is what keeps track of this, and the >> locking contention I was reducing was in the rangelock bookkeeping. > > So, for example, if multiple processes

Re: svn commit: r254380 - in head/sys: kern sys

2013-08-16 Thread Ivan Voras
> We have a single-writer / multiple-readers lock on *any particular byte* > of a vnode. The rangelock code is what keeps track of this, and the > locking contention I was reducing was in the rangelock bookkeeping. So, for example, if multiple processes or multiple threads read or write a file so

Re: svn commit: r254380 - in head/sys: kern sys

2013-08-15 Thread Colin Percival
On 08/15/13 14:34, Ivan Voras wrote: > On 15 August 2013 22:32, Colin Percival wrote: >> No, I wasn't aware that it existed. Given that this change applies only to >> parallel operations *on the same vnode* and blogbench seems to have traffic >> randomly spread between many files, I doubt there w

Re: svn commit: r254380 - in head/sys: kern sys

2013-08-15 Thread Ivan Voras
On 15 August 2013 22:32, Colin Percival wrote: > No, I wasn't aware that it existed. Given that this change applies only to > parallel operations *on the same vnode* and blogbench seems to have traffic > randomly spread between many files, I doubt there would be any difference. Maybe it could h

Re: svn commit: r254380 - in head/sys: kern sys

2013-08-15 Thread Colin Percival
On 08/15/13 13:29, Ivan Voras wrote: > On 15 August 2013 22:19, Colin Percival wrote: >> For workloads with R parallel reads and W parallel writes, this improves >> the time spent from O((R+W)^2) to O(W*(R+W)); i.e., heavy parallel-read >> workloads become significantly more scalable. >> >>

Re: svn commit: r254380 - in head/sys: kern sys

2013-08-15 Thread Ivan Voras
On 15 August 2013 22:19, Colin Percival wrote: > For workloads with R parallel reads and W parallel writes, this improves > the time spent from O((R+W)^2) to O(W*(R+W)); i.e., heavy parallel-read > workloads become significantly more scalable. > > No statistically significant change in bu