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authoralc <alc@FreeBSD.org>2005-02-13 21:51:50 +0000
committeralc <alc@FreeBSD.org>2005-02-13 21:51:50 +0000
commit13e88b41bac03367de7406f96648f28a64fc7322 (patch)
tree57ca8f35daa05acd6944cecccd9aaa5020281122
parent4f2d08a3315df4cdc5b9cf342c6c8f3c29b1b181 (diff)
downloadFreeBSD-src-13e88b41bac03367de7406f96648f28a64fc7322.zip
FreeBSD-src-13e88b41bac03367de7406f96648f28a64fc7322.tar.gz
Request a CPU private mapping from sf_buf_alloc(). If the swap-backed
memory disk is larger than the number of available sf_bufs, this improves performance on SMPs by eliminating interprocessor TLB shootdowns. For example, with 6656 sf_bufs, the default on my test machine, and a 256MB swap-backed memory disk, I see the command "dd if=/dev/md0 of=/dev/null bs=64k" achieve ~489MB/sec with the default, shared mappings, and ~587MB/sec with CPU private mappings.
-rw-r--r--sys/dev/md/md.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/sys/dev/md/md.c b/sys/dev/md/md.c
index 041c511..908d123 100644
--- a/sys/dev/md/md.c
+++ b/sys/dev/md/md.c
@@ -552,13 +552,15 @@ mdstart_swap(struct md_s *sc, struct bio *bp)
m = vm_page_grab(sc->object, i,
VM_ALLOC_NORMAL|VM_ALLOC_RETRY);
VM_OBJECT_UNLOCK(sc->object);
- sf = sf_buf_alloc(m, 0);
+ sched_pin();
+ sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
VM_OBJECT_LOCK(sc->object);
if (bp->bio_cmd == BIO_READ) {
if (m->valid != VM_PAGE_BITS_ALL)
rv = vm_pager_get_pages(sc->object, &m, 1, 0);
if (rv == VM_PAGER_ERROR) {
sf_buf_free(sf);
+ sched_unpin();
vm_page_lock_queues();
vm_page_wakeup(m);
vm_page_unlock_queues();
@@ -570,6 +572,7 @@ mdstart_swap(struct md_s *sc, struct bio *bp)
rv = vm_pager_get_pages(sc->object, &m, 1, 0);
if (rv == VM_PAGER_ERROR) {
sf_buf_free(sf);
+ sched_unpin();
vm_page_lock_queues();
vm_page_wakeup(m);
vm_page_unlock_queues();
@@ -583,6 +586,7 @@ mdstart_swap(struct md_s *sc, struct bio *bp)
rv = vm_pager_get_pages(sc->object, &m, 1, 0);
if (rv == VM_PAGER_ERROR) {
sf_buf_free(sf);
+ sched_unpin();
vm_page_lock_queues();
vm_page_wakeup(m);
vm_page_unlock_queues();
@@ -594,6 +598,7 @@ mdstart_swap(struct md_s *sc, struct bio *bp)
#endif
}
sf_buf_free(sf);
+ sched_unpin();
vm_page_lock_queues();
vm_page_wakeup(m);
vm_page_activate(m);
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