Re: [dpdk-dev] [PATCH 2/3] eventdev: use c11 atomics for lcore timer armed flag

-----Original Message-----
From: Stephen Hemminger <stephen@networkplumber.org>
Sent: Tuesday, June 23, 2020 4:20 PM
To: Phil Yang <redacted>
Cc: dev@dpdk.org; Carrillo, Erik G <redacted>;
drc@linux.vnet.ibm.com; honnappa.nagarahalli@arm.com;
ruifeng.wang@arm.com; dharmik.thakkar@arm.com; nd@arm.com
Subject: Re: [dpdk-dev] [PATCH 2/3] eventdev: use c11 atomics for lcore
timer armed flag

On Fri, 12 Jun 2020 19:19:57 +0800
Phil Yang [off-list ref] wrote:

quoted

 	/* Track which cores have actually armed a timer */
 	struct {
-		rte_atomic16_t v;
+		int16_t v;
 	} __rte_cache_aligned in_use[RTE_MAX_LCORE];

Do you really need this to be cache aligned (ie one per line)?

I believe I did this originally to keep a cache line from bouncing when two different cores are arming timers, so it's not strictly necessary.

Why have a signed value for a reference count? Shouldn't it be unsigned?