Also make sure you have mainline,2030. Without that ata_bd is ridiculously
slow.
-Jiri
---------- Původní zpráva ----------
Od: Jiří Zárevúcky <[email protected]>
Datum: 20. 11. 2013
Předmět: Re: [HelenOS-devel] extremely slow copying
"
On 20 November 2013 16:31, Jakub Jermar <[email protected]
(mailto:[email protected])> wrote:
"
On 20.11.2013 16:23, Dominik Taborsky wrote:
>> On 19 November 2013 19:32, Dominik Taborsky <[email protected]
(mailto:[email protected])> wrote:
>>
>>> Hello,
>>>
>>> I am experiencing very slow file copying. Even a few tens of KiBs takes
>>> seconds, about 25MB is taking two hours and still isn't complete.
>>>
>>>
>> Hi, what filesystem have you used for testing? Last time I saw the code,
>> FAT for example was very slow, due to taking the simple-but-slow-as-hell
>> approach. I suspect even other filesystems have big margins for
>> improvement.
>>
>> -- Jirka Z.
>
> I am actually using FAT. I guess that's explains it, thanks.
On FAT, there used to be the following issue, but got fixed in 2010:
http://www.jakubsuniversalblog.blogspot.cz/2010/08/fat-on-diet.html
(http://www.jakubsuniversalblog.blogspot.cz/2010/08/fat-on-diet.html)
Maybe it broke again or something is defeating the way the fix is
supposed to work. In any case, two hours seems way too much.
"
As far as I can tell, FAT still reads file data a block at a time, making it
much slower than other filesystems. Maybe some other IPC bottleneck made it
this apparent? With 512B blocks, that would make 51 200 IPC data transfers,
128 times the number necessary, which by itself wouldn't explain two hour
copy. Another possibility is that something just crashed or entered infinite
loop.
-- Jirka Z.
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