* [dpdk-stable] [PATCH v2] [18.11] net/mlx5: use open/read/close for ib stats query
@ 2020-12-08 12:45 Viacheslav Ovsiienko
2020-12-08 13:37 ` Kevin Traynor
0 siblings, 1 reply; 2+ messages in thread
From: Viacheslav Ovsiienko @ 2020-12-08 12:45 UTC (permalink / raw)
To: stable; +Cc: ktraynor, mohsinshaikh
From: Mohsin Shaikh <mohsinshaikh@niometrics.com>
[ upstream commit 00437823cb80b8fa87dbe61becc07bd42ee98549 ]
fgets(3)/fread(3)/fscanf(3) etc. use mmap(2)/munmap(2) which leads
to TLB shutdown interrupts to all DPDK app cores including RX cores.
This can cause packet drops. Use read(2)/write(2) instead.
Bugzilla ID: 440
Cc: stable@dpdk.org
Signed-off-by: Mohsin Shaikh <mohsinshaikh@niometrics.com>
Reviewed-by: Alexander Kozyrev <akozyrev@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
---
drivers/net/mlx5/mlx5_stats.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/drivers/net/mlx5/mlx5_stats.c b/drivers/net/mlx5/mlx5_stats.c
index 6906dc8..0b1fe3d 100644
--- a/drivers/net/mlx5/mlx5_stats.c
+++ b/drivers/net/mlx5/mlx5_stats.c
@@ -3,11 +3,13 @@
* Copyright 2015 Mellanox Technologies, Ltd
*/
+#include <fcntl.h>
#include <inttypes.h>
#include <linux/sockios.h>
#include <linux/ethtool.h>
#include <stdint.h>
#include <stdio.h>
+#include <unistd.h>
#include <rte_ethdev_driver.h>
#include <rte_common.h>
@@ -139,19 +141,24 @@
static inline void
mlx5_read_ib_stat(struct mlx5_priv *priv, const char *ctr_name, uint64_t *stat)
{
- FILE *file;
+ int fd;
+
MKSTR(path, "%s/ports/1/hw_counters/%s",
priv->ibdev_path,
ctr_name);
- file = fopen(path, "rb");
- if (file) {
- int n = fscanf(file, "%" SCNu64, stat);
+ fd = open(path, O_RDONLY);
+ if (fd != -1) {
+ char buf[21] = {'\0'};
+ ssize_t n = read(fd, buf, sizeof(buf));
- fclose(file);
- if (n != 1)
- stat = 0;
+ close(fd);
+ if (n != -1) {
+ *stat = strtoull(buf, NULL, 10);
+ return;
+ }
}
+ *stat = 0;
}
/**
--
1.8.3.1
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [dpdk-stable] [PATCH v2] [18.11] net/mlx5: use open/read/close for ib stats query
2020-12-08 12:45 [dpdk-stable] [PATCH v2] [18.11] net/mlx5: use open/read/close for ib stats query Viacheslav Ovsiienko
@ 2020-12-08 13:37 ` Kevin Traynor
0 siblings, 0 replies; 2+ messages in thread
From: Kevin Traynor @ 2020-12-08 13:37 UTC (permalink / raw)
To: Viacheslav Ovsiienko, stable; +Cc: mohsinshaikh
On 08/12/2020 12:45, Viacheslav Ovsiienko wrote:
> From: Mohsin Shaikh <mohsinshaikh@niometrics.com>
>
> [ upstream commit 00437823cb80b8fa87dbe61becc07bd42ee98549 ]
>
> fgets(3)/fread(3)/fscanf(3) etc. use mmap(2)/munmap(2) which leads
> to TLB shutdown interrupts to all DPDK app cores including RX cores.
> This can cause packet drops. Use read(2)/write(2) instead.
>
> Bugzilla ID: 440
> Cc: stable@dpdk.org
>
> Signed-off-by: Mohsin Shaikh <mohsinshaikh@niometrics.com>
> Reviewed-by: Alexander Kozyrev <akozyrev@mellanox.com>
> Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
> ---
> drivers/net/mlx5/mlx5_stats.c | 21 ++++++++++++++-------
> 1 file changed, 14 insertions(+), 7 deletions(-)
Applied, thanks.
^ permalink raw reply [flat|nested] 2+ messages in thread
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