[PC-BSD Testing] upgrading.. slower than needs be

Julian Elischer julian at freebsd.org
Mon Dec 5 10:18:05 PST 2011

On 12/5/11 8:02 AM, Kris Moore wrote:
> On 12/01/2011 21:06, Julian Elischer wrote:
>> On 12/1/11 5:03 PM, Julian Elischer wrote:
>>> Watching the RC1->RC2 upgrade on my nice shiny new 15Mb/sec internet
>>> link, I now see that teh upgrade process does one file at a time.
>>> it would be a lot faster to overlap the downloads if it were
>>> possible. Does the upgrade process know of more than one file that it
>>> needs to get?
>> One could at least make the fetch of the checksum file be done in
>> parallel, so that the tcp handshake is done during the transfer of the
>> main file.
>> Looking at my system upgrading however it looks as though there is
>> something else that should be found too.
>> It's 95 % idle, yet it is only asking for each file, one at a time
>> with large gaps between them.(10 seconds)?
>> Disk I doesn't seem to be  a bottleneck either so I can't work out
>> what the holdup is.
> I'll see what we can do to speed this up :) Parallel downloads would
> help for sure, if anything we can do the md5 at the same time.

unfortunately I have now upgraded so I can't do it again to test, but
I could se no reason as to why it was so slow.

teh disk was barely being touched, and there was only 5% cpu usage, 
and teh network IO was only sporadic.. it would do aburst of high 
bandwidth where it downloaded the file, then there would be a blip 
where it did someting on cpu then a 5 second gap of nothing then the 
md 5 would be received and then another 5 seconds of nothing much, and 
then the cycle would repeat.

I just realised that I took a ktrace of the upgrade and that shoudl 
still be there.  heh.. maybe that has some clues..


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