lkml.org 
[lkml]   [2007]   [Aug]   [5]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
/
DateSun, 05 Aug 2007 13:59:24 -0400
FromJeff Garzik <>
SubjectRe: [PATCH 00/23] per device dirty throttling -v8
Ingo Molnar wrote:
> * Theodore Tso <tytso@mit.edu> wrote:
> 
>> If you are always reading from the same small set of files (i.e., a 
>> database workload), then those inodes only get updated every 5 seconds 
>> (the traditional/default metadata update sync time, as well as the 
>> default ext3 journal update time), it's no big deal.  Or if you are 
>> running a mail server, most of the time the mail queue files are 
>> getting updated anyway as you process them, and usually the mail is 
>> delivered before 5 seconds is up anyway.
>>
>> So earlier, when Ingo characterized it as, "whenever you read from a 
>> file, even one in memory cache.... do a write!", it's probably a bit 
>> unfair.  Traditional Unix systems simply had very different workload 
>> characteristics than many modern dekstop systems today.
> 
> yeah, i didnt mean to say that it is _always_ a big issue, but "only a 
> small number of files are read" is a very, very small minority of even 
> the database server world.

OTOH, consider a popular Linux task, web serving.  atime results in a 
lot of unnecessary disk traffic.

	Jeff



-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-08-05 18:03    [from the cache]
©2003-2008