Re: [dpdk-dev] [Linuxarm] Re: [PATCH V2 04/14] net/hns3: add Rx and Tx bytes stats

在 2021/3/3 22:24, Ferruh Yigit 写道:

On 3/3/2021 2:08 PM, oulijun wrote:

quoted

在 2021/3/3 21:28, Ferruh Yigit 写道:

quoted

On 3/2/2021 1:58 PM, Lijun Ou wrote:

quoted

From: "Min Hu (Connor)" <redacted>

In current HNS3 PMD, Rx/Tx bytes from packet stats are not
implemented.

This patch implemented Rx/Tx bytes using soft counters.
Rx/Tx bytes stats will be enabled if the macro
RTE_LIBRTE_HNS3_PMD_SOFT_COUNTERS is defined.

Signed-off-by: Min Hu (Connor) <redacted>
Signed-off-by: Lijun Ou <redacted>
---
  drivers/net/hns3/hns3_rxtx.c          | 24 ++++++++++++++++++++++++
  drivers/net/hns3/hns3_rxtx_vec_neon.h | 15 +++++++++++++++
  drivers/net/hns3/hns3_rxtx_vec_sve.c  | 11 +++++++++++
  drivers/net/hns3/hns3_stats.c         | 22 ++++++++++++++++++----
  4 files changed, 68 insertions(+), 4 deletions(-)

diff --git a/drivers/net/hns3/hns3_rxtx.c 

b/drivers/net/hns3/hns3_rxtx.c
index 5e79177..a8bd2cc 100644

--- a/drivers/net/hns3/hns3_rxtx.c
+++ b/drivers/net/hns3/hns3_rxtx.c

@@ -2181,6 +2181,10 @@ hns3_recv_pkts(void *rx_queue, struct 

rte_mbuf **rx_pkts, uint16_t nb_pkts)
                             cksum_err);
          hns3_rxd_to_vlan_tci(rxq, rxm, l234_info, &rxd);
+#ifdef RTE_LIBRTE_HNS3_PMD_SOFT_COUNTERS
+        /* Increment bytes counter  */
+        rxq->basic_stats.bytes += rxm->pkt_len;
+#endif

copy/paste from previous version:

Why statistics enabled only with macro?
It is not common to use macro to enable the stats, what do you think 
to remove it, to be consistent with rest of the PMDs?

I'm sorry. I thought it was a success.
  Firstly, the macro is used to control the statistics to ensure 
performance and facilitate flexible usage. For example, the macro 
needs to be disabled when high performance is required.
secondly the byte statistics of other vendors are implemented by 
reading and writing registers. Therefore, macros are not used.By the 
way, the MLX driver has a precedent (code snippets can be intercepted 
here).

It is not convenient for a user re-compile the DPDK to be able to get 
the ethdev byte statistics, stats are not developer/debug information, 
end user may need them. And this recompilation may not be an option for 
the distributed software.

How much performance affect it has if you enable it always?

We theoretically analyzed that being on a critical path might have a 
performance impact. Maybe the actual mountain is negligible.

And just to double check, isn't there a way to get this information from 
HW without calculating it in the driver?

OK

The compile time flags, specially after meson switch, hard to enable and 
a little hidden, it is very easy to have broken code there, that is why 
it better to prevent compile time flags as much as possible.
.

After internal analysis, you can accept your comments and remove macros.
I will fix it.