memory cache to reduce disk IO
|Reported by:||mmazur||Owned by:||charles|
On a freshly installed ubuntu 8.10 the only visible signs of activity on an otherwise idle laptop is disk diode flashing every two seconds. iotop tells me that the only offender is transmission.
Transmission should be more intelligent about when it does reads and writes. Dunno how reads are handled (I'm hoping a reasonable amount of data gets cached on every read), but the writes are obviously suboptimal. With an average download speed of a few tens of kb/s I shouldn't be seeing disk writes more often than, say once per minute or so. It just doesn't make sense to write so little data.
Imho there should be some kind of reasonably-sized buffers (for current disks those should probably be at least a few megs in size) that get synced to disk only when either full or after a fixed amount of time passed since the last sync (a minute sounds to me just about right).
I'm quite certain that this would (a) reduce system load when disk is otherwise busy, since it's easier to deal with sporadic but bigger writes and, more importantly, (b) reduce power consumption, since I'm quite certain that an idly spinning disk uses less power, than a busy one (that last one is why I've marked this bug as having a major severity; laptops are a lot more sensitive to this issue).
Personal side-note: my gf asked ma a week ago to switch her vista to a linux system, since, among other things (like general sluggishness) vista had constant disk activity without an obvious cause. I hope the above is just a quick patch, cause it was kind of a downer to find ubuntu behaving more or less the same way :) (albeit with a known cause, thank the author for iotop, and an ability to fill a bug :)
Change History (75)
comment:42 in reply to: ↑ 41 Changed 7 years ago by Astara
comment:45 Changed 7 years ago by charles
- Summary changed from Inefficient disk usage (lack of read/write scheduling) to memory cache to reduce disk IO