sock_recv_ts_and_drops() unconditionally set sk->sk_stamp for every packet, even if the SOCK_TIMESTAMP flag is not set in the related socket. If selinux is enabled, this cause a cache miss for every packet since sk->sk_stamp and sk->sk_security share the same cacheline. With this change sk_stamp is set only if the SOCK_TIMESTAMP flag is set, and is cleared for the first packet, so that the user perceived behavior is unchanged. This gives up to 5% speed-up under udp-flood with small packets. Signed-off-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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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.
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