[Swift-devel] IO for reading restart log?

[Mihael Hategan]

It's using a buffered reader which is a pretty fast universal solution
in java. Its default buffer size is 8192, so I don't think that's the
problem.

It writes to the same restart log, but I'm not 100% sure on that one.

Mihael

On Fri, 2012-12-14 at 14:05 -0600, Michael Wilde wrote:
> Mihael,
> 
> What read() sizes are used to read in the restart log?
> 
> I'm watching a restart on beagle now of a restart log in which about 200K apps had completed.
> 
> Its going rather slow, and top says that the swift jvm is only using about 10% of one core.  Im wondering if the read() length is very low, which is possibly slowing down the restart when the filesystem on which the .rlog file resides is very congested?
> 
> If so, would a bigger read() buffer size help?
> 
> We can try looking at whats happening with strace, but the restart process looks to me to be IO bound.
> 
> Does the restart process involve also *writing* to the same *or a new) restart log?
> 
> Thanks,
> 
> - Mike
> 
>