Thread (99 messages) 99 messages, 7 authors, 2021-10-29

Re: [dpdk-dev] [PATCH v3 2/5] vhost: implement rte_power_monitor API

From: Xia, Chenbo <hidden>
Date: 2021-09-29 03:01:16

Hi Miao,
quoted hunk ↗ jump to hunk
-----Original Message-----
From: Li, Miao <redacted>
Sent: Friday, September 24, 2021 6:23 PM
To: dev@dpdk.org
Cc: Xia, Chenbo <redacted>; maxime.coquelin@redhat.com; Li, Miao
[off-list ref]
Subject: [PATCH v3 2/5] vhost: implement rte_power_monitor API

This patch defines rte_vhost_power_monitor_cond which is used to pass
some information to vhost driver. The information is including the address
to monitor, the expected value, the mask to extract value read from 'addr',
the value size of monitor address, the match flag used to distinguish the
value used to match something or not match something. Vhost driver can use
these information to fill rte_power_monitor_cond.

Signed-off-by: Miao Li <redacted>
---
 lib/vhost/rte_vhost.h | 41 +++++++++++++++++++++++++++++++++++++++++
 lib/vhost/version.map |  3 +++
 lib/vhost/vhost.c     | 38 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 82 insertions(+)
diff --git a/lib/vhost/rte_vhost.h b/lib/vhost/rte_vhost.h
index 8d875e9322..4e1f2de12f 100644
--- a/lib/vhost/rte_vhost.h
+++ b/lib/vhost/rte_vhost.h
@@ -292,6 +292,30 @@ struct vhost_device_ops {
 	void *reserved[1]; /**< Reserved for future extension */
 };

+/**
+ * Power monitor condition.
+ */
+struct rte_vhost_power_monitor_cond {
+	volatile void *addr;  /**< Address to monitor for changes */
+	/**< If the `mask` is non-zero, location pointed
+	 *   to by `addr` will be read and compared
+	 *   against this value.
+	 */
+	uint64_t val;
Will be read and masked, then compared with this value?
+	uint64_t mask; /**< 64-bit mask to extract value read from `addr` */
+	/**< Data size (in bytes) that will be read from the
+	 *   monitored memory location (`addr`). Can be 1, 2,
+	 *   4, or 8. Supplying any other value will result in
+	 *   an error.
+	 */
+	uint8_t size;
+	/**< If 1, checking if `val` matches something.
+	 *  If 0, checking if `val` *doesn't* match a
+	 *  particular value.
+	 */
If 1, and masked value that read from `addr` equals `val`, drivers can exit the
power-saving state.

If 0, ....

The overall comment can't make me understand how this struct is used if I read
the next patch.
+	uint8_t match;
The comment style is a bit messy here. You can make every comment above variable
Definition (like val/size/match ) or make the first line the same as the variable
line (like addr/mask). 

And please update the release note(release_20_11.rst), it's a new feature.

Thanks,
Chenbo
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