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Date:      Thu, 11 Sep 2014 12:13:35 -0600
From:      David <dajose22@gmail.com>
To:        "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>
Subject:   netmap and jumbo packets
Message-ID:  <CAHYV_8zfb8CfSp5RrK%2BZvV3kbe%2BUnj25SNRTN4dqOPuffSMyJw@mail.gmail.com>

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Hi,

I am learning to use netmap. Currently I got pkt-gen working (without
drivers). When I try to set packet size above 2048 I got an error.

Searching through the code I found in sys/dev/netmap/netmap_mem2.c the size
constrain. I change it like this:

diff --git a/sys/dev/netmap/netmap_mem2.c b/sys/dev/netmap/netmap_mem2.c
index a15a8c7..8c561cb 100644
--- a/sys/dev/netmap/netmap_mem2.c
+++ b/sys/dev/netmap/netmap_mem2.c
@@ -25,6 +25,7 @@

 #ifdef linux
 #include "bsd_glue.h"
+#include <linux/vmalloc.h>
 #endif /* linux */

 #ifdef __APPLE__
@@ -54,7 +55,7 @@ __FBSDID("$FreeBSD: head/sys/dev/netmap/netmap.c 241723
2012-1
 #include <dev/netmap/netmap_kern.h>
 #include "netmap_mem2.h"

-#define NETMAP_BUF_MAX_NUM     20*4096*2       /* large machine */
+#define NETMAP_BUF_MAX_NUM     10*4096*2       /* large machine */

 #define NETMAP_POOL_MAX_NAMSZ  32

@@ -183,7 +184,7 @@ struct netmap_obj_params netmap_params[NETMAP_POOLS_NR]
=3D {
                .num  =3D 200,
        },
        [NETMAP_BUF_POOL] =3D {
-               .size =3D 2048,
+               .size =3D 8192,
                .num  =3D NETMAP_BUF_MAX_NUM,
        },
 };


(first change is not related)

I had to change NETMAP_BUF_MAX_NUM because of the amount of memory needed.


This way I can send packets as big as 8192 (which is what I need). Is there
any problems this will bring on? (maybe decrease the performance or any
other side effect)

thanks

--=20
David D=C3=ADaz Barquero

Ingenier=C3=ADa en Computadores
Tecnol=C3=B3gico de Costa Rica



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