Author: mav
Date: Sat Mar 14 21:15:45 2015
New Revision: 280004
URL: https://svnweb.freebsd.org/changeset/base/280004
Log:
Give block I/O interface multiple (8) execution threads.
On parallel random I/O this allows better utilize wide storage pools.
To not confuse prefetcher on linear I/O, consecutive requests are executed
sequentially, following the same logic as was earlier implemented in CTL.
Benchmarks of virtual AHCI disk, backed by ZVOL on RAID10 pool of 4 HDDs,
show ~3.5 times random read performance improvements, while no degradation
on linear I/O.
MFC after: 2 weeks
Modified:
head/usr.sbin/bhyve/block_if.c
Modified: head/usr.sbin/bhyve/block_if.c
==============================================================================
--- head/usr.sbin/bhyve/block_if.c Sat Mar 14 21:07:37 2015
(r280003)
+++ head/usr.sbin/bhyve/block_if.c Sat Mar 14 21:15:45 2015
(r280004)
@@ -55,6 +55,7 @@ __FBSDID("$FreeBSD$");
#define BLOCKIF_SIG 0xb109b109
#define BLOCKIF_MAXREQ 33
+#define BLOCKIF_NUMTHR 8
enum blockop {
BOP_READ,
@@ -65,6 +66,7 @@ enum blockop {
enum blockstat {
BST_FREE,
+ BST_BLOCK,
BST_PEND,
BST_BUSY,
BST_DONE
@@ -76,6 +78,7 @@ struct blockif_elem {
enum blockop be_op;
enum blockstat be_status;
pthread_t be_tid;
+ off_t be_block;
};
struct blockif_ctxt {
@@ -88,16 +91,15 @@ struct blockif_ctxt {
int bc_sectsz;
int bc_psectsz;
int bc_psectoff;
- pthread_t bc_btid;
+ int bc_closing;
+ pthread_t bc_btid[BLOCKIF_NUMTHR];
pthread_mutex_t bc_mtx;
pthread_cond_t bc_cond;
- int bc_closing;
/* Request elements and free/pending/busy queues */
TAILQ_HEAD(, blockif_elem) bc_freeq;
TAILQ_HEAD(, blockif_elem) bc_pendq;
TAILQ_HEAD(, blockif_elem) bc_busyq;
- u_int bc_req_count;
struct blockif_elem bc_reqs[BLOCKIF_MAXREQ];
};
@@ -116,58 +118,83 @@ static int
blockif_enqueue(struct blockif_ctxt *bc, struct blockif_req *breq,
enum blockop op)
{
- struct blockif_elem *be;
-
- assert(bc->bc_req_count < BLOCKIF_MAXREQ);
+ struct blockif_elem *be, *tbe;
+ off_t off;
+ int i;
be = TAILQ_FIRST(&bc->bc_freeq);
assert(be != NULL);
assert(be->be_status == BST_FREE);
-
TAILQ_REMOVE(&bc->bc_freeq, be, be_link);
- be->be_status = BST_PEND;
be->be_req = breq;
be->be_op = op;
+ switch (op) {
+ case BOP_READ:
+ case BOP_WRITE:
+ case BOP_DELETE:
+ off = breq->br_offset;
+ for (i = 0; i < breq->br_iovcnt; i++)
+ off += breq->br_iov[i].iov_len;
+ break;
+ default:
+ off = OFF_MAX;
+ }
+ be->be_block = off;
+ TAILQ_FOREACH(tbe, &bc->bc_pendq, be_link) {
+ if (tbe->be_block == breq->br_offset)
+ break;
+ }
+ if (tbe == NULL) {
+ TAILQ_FOREACH(tbe, &bc->bc_busyq, be_link) {
+ if (tbe->be_block == breq->br_offset)
+ break;
+ }
+ }
+ if (tbe == NULL)
+ be->be_status = BST_PEND;
+ else
+ be->be_status = BST_BLOCK;
TAILQ_INSERT_TAIL(&bc->bc_pendq, be, be_link);
-
- bc->bc_req_count++;
-
- return (0);
+ return (be->be_status == BST_PEND);
}
static int
-blockif_dequeue(struct blockif_ctxt *bc, struct blockif_elem **bep)
+blockif_dequeue(struct blockif_ctxt *bc, pthread_t t, struct blockif_elem
**bep)
{
struct blockif_elem *be;
- if (bc->bc_req_count == 0)
- return (ENOENT);
-
- be = TAILQ_FIRST(&bc->bc_pendq);
- assert(be != NULL);
- assert(be->be_status == BST_PEND);
+ TAILQ_FOREACH(be, &bc->bc_pendq, be_link) {
+ if (be->be_status == BST_PEND)
+ break;
+ assert(be->be_status == BST_BLOCK);
+ }
+ if (be == NULL)
+ return (0);
TAILQ_REMOVE(&bc->bc_pendq, be, be_link);
be->be_status = BST_BUSY;
- be->be_tid = bc->bc_btid;
+ be->be_tid = t;
TAILQ_INSERT_TAIL(&bc->bc_busyq, be, be_link);
-
*bep = be;
-
- return (0);
+ return (1);
}
static void
blockif_complete(struct blockif_ctxt *bc, struct blockif_elem *be)
{
- assert(be->be_status == BST_DONE);
+ struct blockif_elem *tbe;
- TAILQ_REMOVE(&bc->bc_busyq, be, be_link);
+ if (be->be_status == BST_DONE || be->be_status == BST_BUSY)
+ TAILQ_REMOVE(&bc->bc_busyq, be, be_link);
+ else
+ TAILQ_REMOVE(&bc->bc_pendq, be, be_link);
+ TAILQ_FOREACH(tbe, &bc->bc_pendq, be_link) {
+ if (tbe->be_req->br_offset == be->be_block)
+ tbe->be_status = BST_PEND;
+ }
be->be_tid = 0;
be->be_status = BST_FREE;
be->be_req = NULL;
TAILQ_INSERT_TAIL(&bc->bc_freeq, be, be_link);
-
- bc->bc_req_count--;
}
static void
@@ -226,28 +253,27 @@ blockif_thr(void *arg)
{
struct blockif_ctxt *bc;
struct blockif_elem *be;
+ pthread_t t;
bc = arg;
+ t = pthread_self();
+ pthread_mutex_lock(&bc->bc_mtx);
for (;;) {
- pthread_mutex_lock(&bc->bc_mtx);
- while (!blockif_dequeue(bc, &be)) {
+ while (blockif_dequeue(bc, t, &be)) {
pthread_mutex_unlock(&bc->bc_mtx);
blockif_proc(bc, be);
pthread_mutex_lock(&bc->bc_mtx);
blockif_complete(bc, be);
}
- pthread_cond_wait(&bc->bc_cond, &bc->bc_mtx);
- pthread_mutex_unlock(&bc->bc_mtx);
-
- /*
- * Check ctxt status here to see if exit requested
- */
+ /* Check ctxt status here to see if exit requested */
if (bc->bc_closing)
- pthread_exit(NULL);
+ break;
+ pthread_cond_wait(&bc->bc_cond, &bc->bc_mtx);
}
+ pthread_mutex_unlock(&bc->bc_mtx);
- /* Not reached */
+ pthread_exit(NULL);
return (NULL);
}
@@ -386,16 +412,16 @@ blockif_open(const char *optstr, const c
TAILQ_INIT(&bc->bc_freeq);
TAILQ_INIT(&bc->bc_pendq);
TAILQ_INIT(&bc->bc_busyq);
- bc->bc_req_count = 0;
for (i = 0; i < BLOCKIF_MAXREQ; i++) {
bc->bc_reqs[i].be_status = BST_FREE;
TAILQ_INSERT_HEAD(&bc->bc_freeq, &bc->bc_reqs[i], be_link);
}
- pthread_create(&bc->bc_btid, NULL, blockif_thr, bc);
-
- snprintf(tname, sizeof(tname), "blk-%s", ident);
- pthread_set_name_np(bc->bc_btid, tname);
+ for (i = 0; i < BLOCKIF_NUMTHR; i++) {
+ pthread_create(&bc->bc_btid[i], NULL, blockif_thr, bc);
+ snprintf(tname, sizeof(tname), "blk-%s-%d", ident, i);
+ pthread_set_name_np(bc->bc_btid[i], tname);
+ }
return (bc);
}
@@ -409,13 +435,13 @@ blockif_request(struct blockif_ctxt *bc,
err = 0;
pthread_mutex_lock(&bc->bc_mtx);
- if (bc->bc_req_count < BLOCKIF_MAXREQ) {
+ if (!TAILQ_EMPTY(&bc->bc_freeq)) {
/*
* Enqueue and inform the block i/o thread
* that there is work available
*/
- blockif_enqueue(bc, breq, op);
- pthread_cond_signal(&bc->bc_cond);
+ if (blockif_enqueue(bc, breq, op))
+ pthread_cond_signal(&bc->bc_cond);
} else {
/*
* Callers are not allowed to enqueue more than
@@ -481,11 +507,7 @@ blockif_cancel(struct blockif_ctxt *bc,
/*
* Found it.
*/
- TAILQ_REMOVE(&bc->bc_pendq, be, be_link);
- be->be_status = BST_FREE;
- be->be_req = NULL;
- TAILQ_INSERT_TAIL(&bc->bc_freeq, be, be_link);
- bc->bc_req_count--;
+ blockif_complete(bc, be);
pthread_mutex_unlock(&bc->bc_mtx);
return (0);
@@ -546,7 +568,7 @@ int
blockif_close(struct blockif_ctxt *bc)
{
void *jval;
- int err;
+ int err, i;
err = 0;
@@ -556,8 +578,9 @@ blockif_close(struct blockif_ctxt *bc)
* Stop the block i/o thread
*/
bc->bc_closing = 1;
- pthread_cond_signal(&bc->bc_cond);
- pthread_join(bc->bc_btid, &jval);
+ pthread_cond_broadcast(&bc->bc_cond);
+ for (i = 0; i < BLOCKIF_NUMTHR; i++)
+ pthread_join(bc->bc_btid[i], &jval);
/* XXX Cancel queued i/o's ??? */
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