On 9/28/2020 4:43 PM, Stephen Hemminger wrote:
On Mon, 28 Sep 2020 17:24:26 +0200
Thomas Monjalon <tho...@monjalon.net> wrote:
28/09/2020 15:53, Ferruh Yigit:
On 9/28/2020 10:16 AM, Thomas Monjalon wrote:
28/09/2020 10:59, Ferruh Yigit:
On 9/27/2020 4:16 AM, Min Hu (Connor) wrote:
From: Huisong Li <lihuis...@huawei.com>
Currently, only statistics of rx/tx queues with queue_id less than
RTE_ETHDEV_QUEUE_STAT_CNTRS can be displayed. If there is a certain
application scenario that it needs to use 256 or more than 256 queues
and display all statistics of rx/tx queue. At this moment, we have to
change the macro to be equaled to the queue number.
However, modifying the macro to be greater than 256 will trigger
many errors and warnings from test-pmd, PMD drivers and librte_ethdev
during compiling dpdk project. But it is possible and permitted that
rx/tx queue number is greater than 256 and all statistics of rx/tx
queue need to be displayed. In addition, the data type of rx/tx queue
number in rte_eth_dev_configure API is 'uint16_t'. So It is unreasonable
to use the 'uint8_t' type for variables that control which per-queue
statistics can be displayed.
The explanation is too much complex and misleading.
You mean you cannot increase RTE_ETHDEV_QUEUE_STAT_CNTRS
above 256 because it is an 8-bit type?
[...]
--- a/lib/librte_ethdev/rte_ethdev.h
+++ b/lib/librte_ethdev/rte_ethdev.h
int rte_eth_dev_set_tx_queue_stats_mapping(uint16_t port_id,
- uint16_t tx_queue_id, uint8_t stat_idx);
+ uint16_t tx_queue_id, uint16_t stat_idx);
[...]
int rte_eth_dev_set_rx_queue_stats_mapping(uint16_t port_id,
uint16_t rx_queue_id,
- uint8_t stat_idx);
+ uint16_t stat_idx);
[...]
cc'ed tech-board,
The patch breaks the ethdev ABI without a deprecation notice from previous
release(s).
It is mainly a fix to the port_id storage type, which we have updated from
uint8_t to uint16_t in past but some seems remained for
'rte_eth_dev_set_tx_queue_stats_mapping()' &
'rte_eth_dev_set_rx_queue_stats_mapping()' APIs.
No, it is not related to the port id, but the number of limited stats.
Right, it is not related to the port id, it is fixing the storage type for index
used to map the queue stats.
Since the ethdev library already heavily breaks the ABI this release, I am for
getting this fix, instead of waiting the fix for one more year.
If stats can be managed for more than 256 queues, I think it means
it is not limited. In this case, we probably don't need the API
*_queue_stats_mapping which was invented for a limitation of ixgbe.
The problem is probably somewhere else (in testpmd),
that's why I am against this patch.
This patch is not to fix queue stats mapping, I agree there are problems related
to it, already shared as comment to this set.
But this patch is to fix the build errors when 'RTE_ETHDEV_QUEUE_STAT_CNTRS'
needs to set more than 255. Where the build errors seems around the
stats_mapping APIs.
It is not said this API is supposed to manage more than 256 queues mapping.
In general we should not need this API.
I think it is solving the wrong problem.
The original API is a band aid for the limited number of statistics counters
in the Intel IXGBE hardware. It crept into to the DPDK as an API. I would rather
have per-queue statistics and make ixgbe say "not supported"
The current issue is not directly related to '*_queue_stats_mapping' APIs.
Problem is not able to set 'RTE_ETHDEV_QUEUE_STAT_CNTRS' > 255.
User may need to set the 'RTE_ETHDEV_QUEUE_STAT_CNTRS' > 255, since it is used
to define size of the stats counter.
"uint64_t q_ipackets[RTE_ETHDEV_QUEUE_STAT_CNTRS];"
When 'RTE_ETHDEV_QUEUE_STAT_CNTRS' > 255, it gives multiple build errors, the
one in the ethdev is like [1].
This can be fixed two ways,
a) increase the size of 'stat_idx' storage type to u16 in the
'*_queue_stats_mapping' APIs, this is what this patch does.
b) Fix with a casting in the comparison, without changing the APIs.
I think both are OK, but is (b) more preferable?
[1]
../lib/librte_ethdev/rte_ethdev.c: In function ‘set_queue_stats_mapping’:
../lib/librte_ethdev/rte_ethdev.c:2943:15: warning: comparison is always false
due to limited range of data type [-Wtype-limits]
2943 | if (stat_idx >= RTE_ETHDEV_QUEUE_STAT_CNTRS)
| ^~
