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| author | Arjun Roy <arjunroy@google.com> | 2020-02-15 02:30:49 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-02-17 06:25:02 +0300 |
| commit | c8856c051454909e5059df4e81c77b9c366c5515 (patch) | |
| tree | 72b78bb1392b3d2209b387599d8f15fbb2fcae5c /include/uapi/linux/tcp.h | |
| parent | 8c8da5b8eaf80b9958de96cce189abd4bd1aaff1 (diff) | |
| download | linux-c8856c051454909e5059df4e81c77b9c366c5515.tar.xz | |
tcp-zerocopy: Return inq along with tcp receive zerocopy.
This patchset is intended to reduce the number of extra system calls
imposed by TCP receive zerocopy. For ping-pong RPC style workloads,
this patchset has demonstrated a system call reduction of about 30%
when coupled with userspace changes.
For applications using edge-triggered epoll, returning inq along with
the result of tcp receive zerocopy could remove the need to call
recvmsg()=-EAGAIN after a successful zerocopy. Generally speaking,
since normally we would need to perform a recvmsg() call for every
successful small RPC read via TCP receive zerocopy, returning inq can
reduce the number of system calls performed by approximately half.
Signed-off-by: Arjun Roy <arjunroy@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/uapi/linux/tcp.h')
| -rw-r--r-- | include/uapi/linux/tcp.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index fd9eb8f6bcae..548f480b9c66 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -345,5 +345,6 @@ struct tcp_zerocopy_receive { __u64 address; /* in: address of mapping */ __u32 length; /* in/out: number of bytes to map/mapped */ __u32 recv_skip_hint; /* out: amount of bytes to skip */ + __u32 inq; /* out: amount of bytes in read queue */ }; #endif /* _UAPI_LINUX_TCP_H */ |