Hi,
> -----Original Message-----
> From: dev <dev-boun...@dpdk.org> On Behalf Of Mohsin Shaikh
> Sent: Thursday, April 9, 2020 11:37 PM
> To: dev@dpdk.org
> Cc: sta...@dpdk.org; Alexander Kozyrev <akozy...@mellanox.com>;
> Mohsin Shaikh <mohsinsha...@niometrics.com>
> Subject: [dpdk-dev] [PATCH] net/mlx5: use open/read/close for reading ib
> stat
>
> fgets(3)/fread(3)/fscanf(3) etc. use mmap(2)/munmap(2) which leads
> to TLB shootdown interrupts to all dpdk app cores including RX cores.
> This can cause packet drops. Use read(2)/write(2) instead.
>
> Bugzilla ID: 440
> Cc: sta...@dpdk.org
>
> Signed-off-by: Mohsin Shaikh <mohsinsha...@niometrics.com>
> ---
> drivers/net/mlx5/mlx5_stats.c | 21 +++++++++++++--------
> 1 file changed, 13 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/net/mlx5/mlx5_stats.c b/drivers/net/mlx5/mlx5_stats.c
> index 7603502..b2c09d8 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>
> @@ -142,20 +144,23 @@
> static inline void
> mlx5_read_ib_stat(struct mlx5_priv *priv, const char *ctr_name, uint64_t
> *stat)
> {
> - FILE *file;
> + int fd;
> +
> if (priv->sh) {
> MKSTR(path, "%s/ports/%d/hw_counters/%s",
> priv->sh->ibdev_path,
> priv->ibv_port,
> ctr_name);
> -
> - file = fopen(path, "rb");
> - if (file) {
> - int n = fscanf(file, "%" SCNu64, stat);
> -
> - fclose(file);
> - if (n == 1)
> + fd = open(path, O_RDONLY);
> + if (fd != -1) {
> + char buf[21] = {'\0'};
> + ssize_t n = read(fd, buf, sizeof(buf));
> +
> + close(fd);
> + if (n != -1) {
> + *stat = strtoull(buf, NULL, 10);
> return;
> + }
> }
> }
> *stat = 0;
> --
> 1.8.3.1
Patch rebased and applied to next-net-mlx,
Kindest regards
Raslan Darawsheh
