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author | Paolo Bonzini <pbonzini@redhat.com> | 2015-12-22 12:03:33 +0100 |
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committer | Timothy Pearson <tpearson@raptorengineering.com> | 2019-11-29 19:34:37 -0600 |
commit | 1cfd76af9b5d28d9ce9d33bc372f6e0a858e55cf (patch) | |
tree | abe532685f1e94ca7da3b32eec7e20c2390c11b3 /util/iov.c | |
parent | 13d76bf819f959a3e9d0f140b2b738893369feca (diff) | |
download | hqemu-1cfd76af9b5d28d9ce9d33bc372f6e0a858e55cf.zip hqemu-1cfd76af9b5d28d9ce9d33bc372f6e0a858e55cf.tar.gz |
iov: avoid memcpy for "simple" iov_from_buf/iov_to_buf
memcpy can take a large amount of time for small reads and writes.
For virtio it is a common case that the first iovec can satisfy the
whole read or write. In that case, and if bytes is a constant to
avoid excessive growth of code, inline the first iteration
into the caller.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1450782213-14227-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'util/iov.c')
-rw-r--r-- | util/iov.c | 8 |
1 files changed, 4 insertions, 4 deletions
@@ -20,8 +20,8 @@ #include "qemu/iov.h" #include "qemu/sockets.h" -size_t iov_from_buf(const struct iovec *iov, unsigned int iov_cnt, - size_t offset, const void *buf, size_t bytes) +size_t iov_from_buf_full(const struct iovec *iov, unsigned int iov_cnt, + size_t offset, const void *buf, size_t bytes) { size_t done; unsigned int i; @@ -39,8 +39,8 @@ size_t iov_from_buf(const struct iovec *iov, unsigned int iov_cnt, return done; } -size_t iov_to_buf(const struct iovec *iov, const unsigned int iov_cnt, - size_t offset, void *buf, size_t bytes) +size_t iov_to_buf_full(const struct iovec *iov, const unsigned int iov_cnt, + size_t offset, void *buf, size_t bytes) { size_t done; unsigned int i; |