patches for DPDK stable branches
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* [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

end of thread, other threads:[~2020-12-08 13:38 UTC | newest]

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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

patches for DPDK stable branches

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