043e337f55
In Kernel 4.15.0+, Netem does not work properly. Netem setup: tc qdisc add dev h1-eth0 root handle 1: netem delay 10ms 2ms Result: PING 172.16.101.2 (172.16.101.2) 56(84) bytes of data. 64 bytes from 172.16.101.2: icmp_seq=1 ttl=64 time=22.8 ms 64 bytes from 172.16.101.2: icmp_seq=2 ttl=64 time=10.9 ms 64 bytes from 172.16.101.2: icmp_seq=3 ttl=64 time=10.9 ms 64 bytes from 172.16.101.2: icmp_seq=5 ttl=64 time=11.4 ms 64 bytes from 172.16.101.2: icmp_seq=6 ttl=64 time=11.8 ms 64 bytes from 172.16.101.2: icmp_seq=4 ttl=64 time=4303 ms 64 bytes from 172.16.101.2: icmp_seq=10 ttl=64 time=11.2 ms 64 bytes from 172.16.101.2: icmp_seq=11 ttl=64 time=10.3 ms 64 bytes from 172.16.101.2: icmp_seq=7 ttl=64 time=4304 ms 64 bytes from 172.16.101.2: icmp_seq=8 ttl=64 time=4303 ms Patch: (rnd % (2 * sigma)) - sigma was overflowing s32. After applying the patch, I found following output which is desirable. PING 172.16.101.2 (172.16.101.2) 56(84) bytes of data. 64 bytes from 172.16.101.2: icmp_seq=1 ttl=64 time=21.1 ms 64 bytes from 172.16.101.2: icmp_seq=2 ttl=64 time=8.46 ms 64 bytes from 172.16.101.2: icmp_seq=3 ttl=64 time=9.00 ms 64 bytes from 172.16.101.2: icmp_seq=4 ttl=64 time=11.8 ms 64 bytes from 172.16.101.2: icmp_seq=5 ttl=64 time=8.36 ms 64 bytes from 172.16.101.2: icmp_seq=6 ttl=64 time=11.8 ms 64 bytes from 172.16.101.2: icmp_seq=7 ttl=64 time=8.11 ms 64 bytes from 172.16.101.2: icmp_seq=8 ttl=64 time=10.0 ms 64 bytes from 172.16.101.2: icmp_seq=9 ttl=64 time=11.3 ms 64 bytes from 172.16.101.2: icmp_seq=10 ttl=64 time=11.5 ms 64 bytes from 172.16.101.2: icmp_seq=11 ttl=64 time=10.2 ms Reviewed-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.