FEX-Emu/linux
1
0
Fork 0
mirror of https://github.com/FEX-Emu/linux.git synced 2024-12-28 20:37:27 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

IB/qib: Change SDMA progression mode depending on single- or multi-rail

Browse Source 
Improve performance by changing the behavour of the driver when all
SDMA descriptors are in use, and the processes adding new descriptors
are single- or multi-rail.

For single-rail processes, the driver will block the call and finish
posting all SDMA descriptors onto the hardware queue before returning
back to PSM.  Repeated kernel calls are slower than blocking.

For multi-rail processes, the driver will return to PSM as quick as
possible so PSM can feed packets to other rail.  If all hardware
queues are full, PSM will buffer the remaining SDMA descriptors until
notified by interrupt that space is available.

This patch builds a red-black tree to track the number rails opened by
a particular PID. If the number is more than one, it is a multi-rail
PSM process, otherwise, it is a single-rail process.

Reviewed-by: Dean Luick <dean.luick@intel.com>
Reviewed-by: John A Gregor <john.a.gregor@intel.com>
Reviewed-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: CQ Tang <cq.tang@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
This commit is contained in:
CQ Tang 2014-01-30 17:36:00 -05:00 committed by Roland Dreier
parent db498827ff
commit 49c0e2414b
1 changed files with 124 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

138
drivers/infiniband/hw/qib/qib_user_sdma.c
View File

@ -52,6 +52,17 @@
/* attempt to drain the queue for 5secs */
#define QIB_USER_SDMA_DRAIN_TIMEOUT 500
/*
* track how many times a process open this driver.
*/
static struct rb_root qib_user_sdma_rb_root = RB_ROOT;
struct qib_user_sdma_rb_node {
struct rb_node node;
int refcount;
pid_t pid;
};
struct qib_user_sdma_pkt {
struct list_head list; /* list element */
@ -120,15 +131,60 @@ struct qib_user_sdma_queue {
/* dma page table */
struct rb_root dma_pages_root;
struct qib_user_sdma_rb_node *sdma_rb_node;
/* protect everything above... */
struct mutex lock;
};
static struct qib_user_sdma_rb_node *
qib_user_sdma_rb_search(struct rb_root *root, pid_t pid)
{
struct qib_user_sdma_rb_node *sdma_rb_node;
struct rb_node *node = root->rb_node;
while (node) {
sdma_rb_node = container_of(node,
struct qib_user_sdma_rb_node, node);
if (pid < sdma_rb_node->pid)
node = node->rb_left;
else if (pid > sdma_rb_node->pid)
node = node->rb_right;
else
return sdma_rb_node;
}
return NULL;
}
static int
qib_user_sdma_rb_insert(struct rb_root *root, struct qib_user_sdma_rb_node *new)
{
struct rb_node **node = &(root->rb_node);
struct rb_node *parent = NULL;
struct qib_user_sdma_rb_node *got;
while (*node) {
got = container_of(*node, struct qib_user_sdma_rb_node, node);
parent = *node;
if (new->pid < got->pid)
node = &((*node)->rb_left);
else if (new->pid > got->pid)
node = &((*node)->rb_right);
else
return 0;
}
rb_link_node(&new->node, parent, node);
rb_insert_color(&new->node, root);
return 1;
}
struct qib_user_sdma_queue *
qib_user_sdma_queue_create(struct device *dev, int unit, int ctxt, int sctxt)
{
struct qib_user_sdma_queue *pq =
kmalloc(sizeof(struct qib_user_sdma_queue), GFP_KERNEL);
struct qib_user_sdma_rb_node *sdma_rb_node;
if (!pq)
goto done;
@ -138,6 +194,7 @@ qib_user_sdma_queue_create(struct device *dev, int unit, int ctxt, int sctxt)
pq->num_pending = 0;
pq->num_sending = 0;
pq->added = 0;
pq->sdma_rb_node = NULL;
INIT_LIST_HEAD(&pq->sent);
spin_lock_init(&pq->sent_lock);
@ -163,8 +220,30 @@ qib_user_sdma_queue_create(struct device *dev, int unit, int ctxt, int sctxt)
pq->dma_pages_root = RB_ROOT;
sdma_rb_node = qib_user_sdma_rb_search(&qib_user_sdma_rb_root,
current->pid);
if (sdma_rb_node) {
sdma_rb_node->refcount++;
} else {
int ret;
sdma_rb_node = kmalloc(sizeof(
struct qib_user_sdma_rb_node), GFP_KERNEL);
if (!sdma_rb_node)
goto err_rb;
sdma_rb_node->refcount = 1;
sdma_rb_node->pid = current->pid;
ret = qib_user_sdma_rb_insert(&qib_user_sdma_rb_root,
sdma_rb_node);
BUG_ON(ret == 0);
}
pq->sdma_rb_node = sdma_rb_node;
goto done;
err_rb:
dma_pool_destroy(pq->header_cache);
err_slab:
kmem_cache_destroy(pq->pkt_slab);
err_kfree:
@ -1020,8 +1099,13 @@ void qib_user_sdma_queue_destroy(struct qib_user_sdma_queue *pq)
if (!pq)
return;
kmem_cache_destroy(pq->pkt_slab);
pq->sdma_rb_node->refcount--;
if (pq->sdma_rb_node->refcount == 0) {
rb_erase(&pq->sdma_rb_node->node, &qib_user_sdma_rb_root);
kfree(pq->sdma_rb_node);
}
dma_pool_destroy(pq->header_cache);
kmem_cache_destroy(pq->pkt_slab);
kfree(pq);
}
@ -1241,26 +1325,52 @@ static int qib_user_sdma_push_pkts(struct qib_pportdata *ppd,
struct qib_user_sdma_queue *pq,
struct list_head *pktlist, int count)
{
int ret = 0;
unsigned long flags;
if (unlikely(!(ppd->lflags & QIBL_LINKACTIVE)))
return -ECOMM;
spin_lock_irqsave(&ppd->sdma_lock, flags);
if (unlikely(!__qib_sdma_running(ppd))) {
ret = -ECOMM;
goto unlock;
/* non-blocking mode */
if (pq->sdma_rb_node->refcount > 1) {
spin_lock_irqsave(&ppd->sdma_lock, flags);
if (unlikely(!__qib_sdma_running(ppd))) {
spin_unlock_irqrestore(&ppd->sdma_lock, flags);
return -ECOMM;
}
pq->num_pending += count;
list_splice_tail_init(pktlist, &ppd->sdma_userpending);
qib_user_sdma_send_desc(ppd, &ppd->sdma_userpending);
spin_unlock_irqrestore(&ppd->sdma_lock, flags);
return 0;
}
pq->num_pending += count;
list_splice_tail_init(pktlist, &ppd->sdma_userpending);
qib_user_sdma_send_desc(ppd, &ppd->sdma_userpending);
/* In this case, descriptors from this process are not
* linked to ppd pending queue, interrupt handler
* won't update this process, it is OK to directly
* modify without sdma lock.
*/
unlock:
spin_unlock_irqrestore(&ppd->sdma_lock, flags);
return ret;
pq->num_pending += count;
/*
* Blocking mode for single rail process, we must
* release/regain sdma_lock to give other process
* chance to make progress. This is important for
* performance.
*/
do {
spin_lock_irqsave(&ppd->sdma_lock, flags);
if (unlikely(!__qib_sdma_running(ppd))) {
spin_unlock_irqrestore(&ppd->sdma_lock, flags);
return -ECOMM;
}
qib_user_sdma_send_desc(ppd, pktlist);
if (!list_empty(pktlist))
qib_sdma_make_progress(ppd);
spin_unlock_irqrestore(&ppd->sdma_lock, flags);
} while (!list_empty(pktlist));
return 0;
}
int qib_user_sdma_writev(struct qib_ctxtdata *rcd,
@ -1290,7 +1400,7 @@ int qib_user_sdma_writev(struct qib_ctxtdata *rcd,
qib_user_sdma_queue_clean(ppd, pq);
while (dim) {
int mxp = 8;
int mxp = 1;
int ndesc = 0;
ret = qib_user_sdma_queue_pkts(dd, ppd, pq,