Re: Yet another base64 patch
- From
- Christopher Li <git@chrisli.org>
- Date
- Apr 14, 2005, 02:42 UTC
- Message-ID
- <20050414024228.GC18655@64m.dyndns.org>
- In-Reply-To
- <425E0174.4080404@zytor.com>
On Wed, Apr 13, 2005 at 10:36:52PM -0700, H. Peter Anvin wrote:
Show 11 quoted lines
> Christopher Li wrote: > >On Wed, Apr 13, 2005 at 09:19:48PM -0700, H. Peter Anvin wrote: > > > >That is not surprising due to the directory index in ext3. Htree is pretty > >good at random access and the hashed file name distribute evenly, that is > >the best case for htree. > > > > Right, so by not trying to do the filesystem's job for it we actually > come out ahead. >
But if you write a large number of random files, when htree has three levels index. htree will suffer on the effect that it dirty random block very quickly, most block get dirty only contain one or two new entries. Ext3 will choke on it due to the limited journal size.
While non-index directory, new entry are very compact on the blocks. So it end up dirty a lot less blocks, of course, lookup will suffer.
Depend on you want check out fast or write a big tree fast, you can't win it all.
Chris