Diffstat (limited to 'Documentation/networking/pktgen.txt')
1 files changed, 30 insertions, 26 deletions
diff --git a/Documentation/networking/pktgen.txt b/Documentation/networking/pktgen.txt
index 560c84ba9abd..fa0ad87e6597 100644
@@ -3,11 +3,11 @@
HOWTO for the linux packet generator
-Enable CONFIG_NET_PKTGEN to compile and build pktgen.o either in kernel
-or as module. Module is preferred. insmod pktgen if needed. Once running
-pktgen creates a thread on each CPU where each thread has affinity to its CPU.
-Monitoring and controlling is done via /proc. Easiest to select a suitable
-a sample script and configure.
+Enable CONFIG_NET_PKTGEN to compile and build pktgen.o either in-kernel
+or as a module. A module is preferred; insmod pktgen if needed. Once
+running, pktgen creates a thread for each CPU with affinity to that CPU.
+Monitoring and controlling is done via /proc. It is easiest to select a
+suitable sample script and configure that.
On a dual CPU:
@@ -25,7 +25,7 @@ For monitoring and control pktgen creates:
Tuning NIC for max performance
-The default NIC setting are (likely) not tuned for pktgen's artificial
+The default NIC settings are (likely) not tuned for pktgen's artificial
overload type of benchmarking, as this could hurt the normal use-case.
Specifically increasing the TX ring buffer in the NIC:
@@ -33,20 +33,20 @@ Specifically increasing the TX ring buffer in the NIC:
A larger TX ring can improve pktgen's performance, while it can hurt
in the general case, 1) because the TX ring buffer might get larger
-than the CPUs L1/L2 cache, 2) because it allow more queueing in the
+than the CPU's L1/L2 cache, 2) because it allows more queueing in the
NIC HW layer (which is bad for bufferbloat).
-One should be careful to conclude, that packets/descriptors in the HW
+One should hesitate to conclude that packets/descriptors in the HW
TX ring cause delay. Drivers usually delay cleaning up the
-ring-buffers (for various performance reasons), thus packets stalling
-the TX ring, might just be waiting for cleanup.
+ring-buffers for various performance reasons, and packets stalling
+the TX ring might just be waiting for cleanup.
-This cleanup issues is specifically the case, for the driver ixgbe
-(Intel 82599 chip). This driver (ixgbe) combine TX+RX ring cleanups,
+This cleanup issue is specifically the case for the driver ixgbe
+(Intel 82599 chip). This driver (ixgbe) combines TX+RX ring cleanups,
and the cleanup interval is affected by the ethtool --coalesce setting
of parameter "rx-usecs".
-For ixgbe use e.g "30" resulting in approx 33K interrupts/sec (1/30*10^6):
+For ixgbe use e.g. "30" resulting in approx 33K interrupts/sec (1/30*10^6):
# ethtool -C ethX rx-usecs 30
@@ -58,15 +58,16 @@ Running:
Result: OK: max_before_softirq=10000
-Most important the devices assigned to thread. Note! A device can only belong
-to one thread.
+Most important are the devices assigned to the thread. Note that a
+device can only belong to one thread.
-Parm section holds configured info. Current hold running stats.
-Result is printed after run or after interruption. Example:
+The Params section holds configured information. The Current section
+holds running statistics. The Result is printed after a run or after
@@ -91,7 +92,8 @@ Result: OK: 13101142(c12220741+d880401) usec, 10000000 (60byte,0frags)
Configuring threads and devices
-This is done via the /proc interface easiest done via pgset in the scripts
+This is done via the /proc interface, and most easily done via pgset in
@@ -193,7 +195,8 @@ Examples:
-A collection of small tutorial scripts for pktgen is in examples dir.
+A collection of small tutorial scripts for pktgen is in the examples
pktgen.conf-1-1 # 1 CPU 1 dev
pktgen.conf-1-2 # 1 CPU 2 dev
@@ -204,25 +207,26 @@ pktgen.conf-1-1-ip6 # 1 CPU 1 dev ipv6
pktgen.conf-1-1-ip6-rdos # 1 CPU 1 dev ipv6 w. route DoS
pktgen.conf-1-1-flows # 1 CPU 1 dev multiple flows.
-Run in shell: ./pktgen.conf-X-Y It does all the setup including sending.
+Run in shell: ./pktgen.conf-X-Y
+This does all the setup including sending.
-Note when adding devices to a specific CPU there good idea to also assign
-/proc/irq/XX/smp_affinity so the TX-interrupts gets bound to the same CPU.
-as this reduces cache bouncing when freeing skb's.
+Note that when adding devices to a specific CPU it is a good idea to
+also assign /proc/irq/XX/smp_affinity so that the TX interrupts are bound
+to the same CPU. This reduces cache bouncing when freeing skbs.
-Default IPsec transformation with ESP encapsulation plus Transport mode
-could be enabled by simply setting:
+Default IPsec transformation with ESP encapsulation plus transport mode
+can be enabled by simply setting:
pgset "flag IPSEC"
pgset "flows 1"
To avoid breaking existing testbed scripts for using AH type and tunnel mode,
-user could use "pgset spi SPI_VALUE" to specify which formal of transformation
+you can use "pgset spi SPI_VALUE" to specify which transformation mode