IPC semaphores in varnishtest

Dag Haavi Finstad daghf at varnish-software.com
Tue Dec 22 18:06:13 CET 2015

Hey Dridi,

That looks pretty cool. Having a separate initialisation step and
doing the syncing via a socket sounds like a cleaner approach than
what I did.

I didn't spend all that much time on my ipcsema thing, so not to worry. :-)


On Tue, Dec 22, 2015 at 5:13 PM, Dridi Boukelmoune <dridi at varni.sh> wrote:
> On Tue, Dec 22, 2015 at 3:46 PM, Dag Haavi Finstad
> <daghf at varnish-software.com> wrote:
>> Hi guys
>> At the latest dev meeting in Rotterdam it was brought up that it would
>> be a useful addition to be able to sync a varnishtest semaphore with
>> Varnish itself.
>> snip
>> Please take a look - any ideas or feedback will be most welcome.
> Hi Dag,
> I sent a similar patch set off-list last night and we had offline
> discussions on IPC sema in varnishtest. The consensus is to retire
> semaphores in their current state and introduce non-cyclic barriers
> that would need to be explicitly initialized and would work in either
> local (cond) or shared (socket) mode.
> The syntax will look like this:
>> # initialization
>> barrier b1 cond 2
>> barrier b2 socket 2
>> # usage in varnishtest, you don't "sync N" anymore
>> barrier b1 sync
>> # usage in VCL
>> debug.barrier_sync("${b2_sock}");
> I'll send patches to the list, that's unfortunate that we worked on
> the same thing around the same time :(
> Cheers,
> Dridi

Dag Haavi Finstad
Software Developer | Varnish Software
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