In the code I don't understand on what the wakeup operate nor on what the
blocking operate.

        if (!random_context.seeded) {
#ifndef __OSV__
                selwakeuppri(&random_context.rsel, PUSER);

random_context does not look like a wait condition it look strange.

On Fri, Oct 14, 2016 at 3:57 PM, Tomasz Grabiec <>

> On Fri, Oct 14, 2016 at 3:39 PM, Benoît Canet <
> > wrote:
>> Hello list,
>> In the process of porting go to OSv I noticed that the Go runtime
>> initialization stall half the time waiting in a read for /dev/urandom.
>> The message OSv output is "random: blocking on read.".
>> It then sometime proceeed to unblock itself a couple dozen of seconds
>> later.
>> Does it ring a bell ? Is it expected behavior from /dev/urandom ?
> It looks like entropy pool was depleted. Maybe no hardware entropy sources
> were detected and we were using only slow interrupt entropy harvesting.
> Another option is that you are using virtio-rng and entropy was depleted
> on your host. Check with `cat /proc/sys/kernel/random/entropy_avail`
> Which hypervisor are you running on?
> Can you show your debug console output?

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