mdbx: avoids using pwritev() for single-writes (up to 10% speedup for some kernels & scenarios).

Change-Id: I71fbf0e113b1de4d05b2a43e8532a977c42b8f91
This commit is contained in:
Leonid Yuriev 2020-05-29 17:01:13 +03:00
parent c9f461c4eb
commit 0146b3e2c0

View File

@ -7567,17 +7567,25 @@ static int mdbx_flush_iov(MDBX_txn *const txn, struct iovec *iov,
unsigned iov_items, size_t iov_off,
size_t iov_bytes) {
MDBX_env *const env = txn->mt_env;
int rc = mdbx_pwritev(env->me_lazy_fd, iov, iov_items, iov_off, iov_bytes);
if (unlikely(rc != MDBX_SUCCESS)) {
mdbx_error("Write error: %s", mdbx_strerror(rc));
txn->mt_flags |= MDBX_TXN_ERROR;
mdbx_assert(env, iov_items > 0);
if (likely(iov_items == 1)) {
mdbx_assert(env, iov->iov_len == iov_bytes);
int rc = mdbx_pwrite(env->me_lazy_fd, iov->iov_base, iov_bytes, iov_off);
mdbx_dpage_free(env, (MDBX_page *)iov->iov_base,
bytes2pgno(env, iov_bytes));
return rc;
} else {
int rc = mdbx_pwritev(env->me_lazy_fd, iov, iov_items, iov_off, iov_bytes);
if (unlikely(rc != MDBX_SUCCESS)) {
mdbx_error("Write error: %s", mdbx_strerror(rc));
txn->mt_flags |= MDBX_TXN_ERROR;
}
for (unsigned i = 0; i < iov_items; i++)
mdbx_dpage_free(env, (MDBX_page *)iov[i].iov_base,
bytes2pgno(env, iov[i].iov_len));
return rc;
}
for (unsigned i = 0; i < iov_items; i++)
mdbx_dpage_free(env, (MDBX_page *)iov[i].iov_base,
bytes2pgno(env, iov[i].iov_len));
return rc;
}
/* Flush (some) dirty pages to the map, after clearing their dirty flag.