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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-10-11 10:22:12 (GMT) |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-10-12 19:35:25 (GMT) |
| commit | 29b4433d991c88d86ca48a4c1cc33c671475be4b (patch) | |
| tree | 2ad21b86aab8193c4533820c40cd31af97a7377f /drivers/infiniband/hw/nes/nes_verbs.c | |
| parent | f0b9f4725180ea58c8da78b3de0b4e0ad180fc2c (diff) | |
| download | linux-fsl-qoriq-29b4433d991c88d86ca48a4c1cc33c671475be4b.tar.xz | |
net: percpu net_device refcount
We tried very hard to remove all possible dev_hold()/dev_put() pairs in
network stack, using RCU conversions.
There is still an unavoidable device refcount change for every dst we
create/destroy, and this can slow down some workloads (routers or some
app servers, mmap af_packet)
We can switch to a percpu refcount implementation, now dynamic per_cpu
infrastructure is mature. On a 64 cpus machine, this consumes 256 bytes
per device.
On x86, dev_hold(dev) code :
before
lock incl 0x280(%ebx)
after:
movl 0x260(%ebx),%eax
incl fs:(%eax)
Stress bench :
(Sending 160.000.000 UDP frames,
IP route cache disabled, dual E5540 @2.53GHz,
32bit kernel, FIB_TRIE)
Before:
real 1m1.662s
user 0m14.373s
sys 12m55.960s
After:
real 0m51.179s
user 0m15.329s
sys 10m15.942s
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/infiniband/hw/nes/nes_verbs.c')
| -rw-r--r-- | drivers/infiniband/hw/nes/nes_verbs.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/infiniband/hw/nes/nes_verbs.c b/drivers/infiniband/hw/nes/nes_verbs.c index 9046e66..546fc22 100644 --- a/drivers/infiniband/hw/nes/nes_verbs.c +++ b/drivers/infiniband/hw/nes/nes_verbs.c @@ -785,7 +785,7 @@ static struct ib_pd *nes_alloc_pd(struct ib_device *ibdev, nes_debug(NES_DBG_PD, "nesvnic=%p, netdev=%p %s, ibdev=%p, context=%p, netdev refcnt=%u\n", nesvnic, nesdev->netdev[0], nesdev->netdev[0]->name, ibdev, context, - atomic_read(&nesvnic->netdev->refcnt)); + netdev_refcnt_read(nesvnic->netdev)); err = nes_alloc_resource(nesadapter, nesadapter->allocated_pds, nesadapter->max_pd, &pd_num, &nesadapter->next_pd); @@ -1416,7 +1416,7 @@ static struct ib_qp *nes_create_qp(struct ib_pd *ibpd, /* update the QP table */ nesdev->nesadapter->qp_table[nesqp->hwqp.qp_id-NES_FIRST_QPN] = nesqp; nes_debug(NES_DBG_QP, "netdev refcnt=%u\n", - atomic_read(&nesvnic->netdev->refcnt)); + netdev_refcnt_read(nesvnic->netdev)); return &nesqp->ibqp; } |