четверг, 30 апреля 2015 г., 21:53:30 UTC+6 пользователь Nikolaus Rath 
написал:
>
> > I was transfering files with tar c|dd|ssh s3qluser@s3ql_host tar xC 
> > /s3ql_mount kill -USR1 $dd_pid shows the speed.  It starts from 5M/sec 
> > and falls to 5k/s or even freeze. 
>
> Well, did it fall to 5 k/s or did it freeze? 
>
dd shows 5k/s
If i did s3qlctrl flushcache then according to precise size of transferred 
its freeze.
 

> >>   I see almost 16 connections with s3 servers, but tcpdump shows small 
> >> rate 
> >> > of uploading PUTs. 
> >> 
> >> What do you mean with small? What do you expect it to be, and what did 
> >> you find instead? 
> >> 
> > 200 bytes - 1k  per file. 
> > The dirty size was big (1-2GiB). 
>
> No, I was talking about the small rate of PUTs that you saw in tcpdump. 
>
> If we assume about 100 ms network latency, then with 200 byte files 
> you'd be able to transfer at most 200 bytes / 100 ms = 2 kB/s for each 
> active thread. So your 5 kb/s isn't completely the wrong order of 
> magnitude. 
>
> I would expect that the initial fast period is just when you file up 
> your cache. Am I right that, if you set the cache to something small 
> (say 2 * <number of threads> entries), you're getting a constant 
> transfer rate from the very beginning? 
>
> In tcpdump, how many PUTs do you see per second? Is that number constant? 
>
All right, but why only 16 threads were transferring?

>   
> >> How did you determine that? 
> > 
> > strace -fp $mount.s3ql_pid showed many  FUTEX messages. 
>
> I think that doesn't mean that there's lock contention, just that locks 
> are being used. 
>
 Ok. 256 threads are running much nicely

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