Thanks for the feedback :-) Alex Tomas wrote: > hmm. so you trade 265% degradation of creation for 40% improvement of > unlink? > 265% degradation is only for creating 50000 empty directories. This is not a common case. There are 13% improvement on create 15 files in each directories. Total time on creating these directories and files are 25m6s VS. 24m86s, indeed, dir inode reservation is a little faster. Maybe most of the people will not create dozens of empty directories in their applications, therefore IMHO the 265% degradation is acceptable. If user really need to create so many empty directories, they also can mount the file system without dir inode reservation to get better performance. > thanks, Alex > > Coly Li wrote: >> normal ext4 ext4 with dir inode reservation >> mount options: -o data=writeback -o >> data=writeback,dir_ireserve=low >> Create dirs: real 0m49.101s real 2m59.703s >> Create files: real 24m17.962s real 21m8.161s >> Unlink all: real 24m43.788s real 17m29.862s >> Creating dirs with dir inode reservation is slower than normal ext4 as >> predicted, because allocating >> directory inodes in non-linear order will cause extra hard disk >> seeking and block I/O. Creating >> files with dir inode reservation is 13% faster than normal ext4. >> Unlink all the directories and >> files is 29.2% faster as expected. >> When number of directories is increased, the performance improvement >> will be more considerable. More >> benchmark result will be posted here if necessary, because I need more >> time to run more test cases. > -- Coly Li SuSE PRC Labs - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
