ipxe http download hangs

[nicolas_o]

Bringing up this old story (I am the OP).

The problem of hanging http download did not occur with commit 149b5023. So I originally settled for this commit for our instance of ipxe used in production. We are kickstarting linux with large initrd files (several hundred MBs) many times a day, on a congested network with a lot of broadcast traffic (around 100 packets/s). We typically kickstart several machines at the same time from the same http server (i.e. 10 machines)

More recently we extended usage of ipxe and we needed the menu functions, which were introduced later. So I compiled the HEAD of ipxe and found the hanging http download issue to be back: it would hang at a random percentage. Hitting ctrl-c would restart the download. It occured very frequently.

Then I tried to bisect the issue by hand and I found that:

* commit a87c0c (jul 20 2012) had both the menu functionality I needded and did not show hang behaviour. This is the one I am using in production now. I had to cherry-pick 1ac62b and eb5a2ba to fix some compiler warnings on gcc 4.9
* Later commit 71727 (nov 21, 2012) did not hang, but http download was much slower.
* similar behaviour with later commit e523 (aug 14 2013): no hang, but slower download
* current HEAD (e905cdc) shows frequent hangs as described above

Based on this, it seems that http download performance of ipxe has degraded since 2012, first by download speed slowing down, then hanging altogether.