On Wed, Sep 29, 2021 at 02:32:02PM +0100, Bruce Richardson wrote: > On Wed, Sep 29, 2021 at 01:28:53PM +0100, Kevin Traynor wrote: > > Hi Bruce, > > > > On 24/09/2021 17:18, Bruce Richardson wrote: > > > When DPDK is run with --in-memory mode, multiple processes can run > > > simultaneously using the same runtime dir. This leads to each process > > > removing another process' telemetry socket as it started up, giving > > > unexpected behaviour. > > > > > > This patch changes that behaviour to first check if the existing socket > > > is active. If not, it's an old socket to be cleaned up and can be > > > removed. If it is active, telemetry initialization fails and an error > > > message is printed out giving instructions on how to remove the error; > > > either by using file-prefix to have a different runtime dir (and > > > therefore socket path) or by disabling telemetry if it not needed. > > > > > > > telemetry is enabled by default but it may not be used by the application. > > Hitting this issue will cause rte_eal_init() to fail which will probably > > stop or severely limit the application. > > > > So it could change a working application to a non-working one (albeit one > > that doesn't interfere with other process' sockets). > > > > Can it just print a warning that telemetry will not be enabled and continue > > so it's not returning an rte_eal_init failure? > > > > For a backported fix, yes, that would probably be better behaviour, but for > the latest branch, I think returning error and having the user explicitly > choose the resolution they want to occur is best. I'll see about doing a > separate backport patch for 20.11. > > > A more minor thing, I see it changes the behaviour from, last one runs with > > telemetry, to, first one runs with telemetry. Though it can be figured from > > the commit message, it might be worth calling that change out explicitly. > > > > Sure. I'll resubmit a new version of this without stable CC'ed and include > that behaviour change explicitly in the commit log. > Actually, subtle behaviour change would be in the backport version that doesn't error out, so I'll note it there when doing that patch, not in the v3 of this one.
/Bruce
