projects / people / pmueller / ipfire-2.x.git / blame
| Commit | Line | Data |
|---|---|---|
| 82094b55 AF |
1 | From: Gerald Schaefer <geraldsc@de.ibm.com> |
| 2 | Subject: [PATCH] zfcp: optimize zfcp_qdio_account | |
| 3 | References: bnc#532063,LTC#55526 | |
| 4 | ||
| 5 | From: Heiko Carstens <heiko.carstens@de.ibm.com> | |
| 6 | ||
| 7 | Remove expensive ktime_get()/ktime_us_delta() functions from the hot | |
| 8 | path and use get_clock_monotonic() instead. | |
| 9 | This elimates seven function calls and avoids a lot of unnecessary | |
| 10 | calculations. | |
| 11 | ||
| 12 | Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> | |
| 13 | ||
| 14 | Acked-by: John Jolly <jjolly@suse.de> | |
| 15 | --- | |
| 16 | ||
| 17 | drivers/s390/scsi/zfcp_def.h | 2 +- | |
| 18 | drivers/s390/scsi/zfcp_qdio.c | 11 +++++------ | |
| 19 | 2 files changed, 6 insertions(+), 7 deletions(-) | |
| 20 | ||
| 21 | Index: linux-sles11/drivers/s390/scsi/zfcp_def.h | |
| 22 | =================================================================== | |
| 23 | --- linux-sles11.orig/drivers/s390/scsi/zfcp_def.h 2009-08-17 15:31:27.000000000 +0200 | |
| 24 | +++ linux-sles11/drivers/s390/scsi/zfcp_def.h 2009-08-17 15:31:29.000000000 +0200 | |
| 25 | @@ -472,7 +472,7 @@ | |
| 26 | spinlock_t req_q_lock; /* for operations on queue */ | |
| 27 | int req_q_pci_batch; /* SBALs since PCI indication | |
| 28 | was last set */ | |
| 29 | - ktime_t req_q_time; /* time of last fill level change */ | |
| 30 | + unsigned long long req_q_time; /* time of last fill level change */ | |
| 31 | u64 req_q_util; /* for accounting */ | |
| 32 | spinlock_t qdio_stat_lock; | |
| 33 | u32 fsf_req_seq_no; /* FSF cmnd seq number */ | |
| 34 | Index: linux-sles11/drivers/s390/scsi/zfcp_qdio.c | |
| 35 | =================================================================== | |
| 36 | --- linux-sles11.orig/drivers/s390/scsi/zfcp_qdio.c 2009-08-17 15:31:27.000000000 +0200 | |
| 37 | +++ linux-sles11/drivers/s390/scsi/zfcp_qdio.c 2009-08-17 15:31:29.000000000 +0200 | |
| 38 | @@ -77,16 +77,15 @@ | |
| 39 | } | |
| 40 | ||
| 41 | /* this needs to be called prior to updating the queue fill level */ | |
| 42 | -static void zfcp_qdio_account(struct zfcp_adapter *adapter) | |
| 43 | +static inline void zfcp_qdio_account(struct zfcp_adapter *adapter) | |
| 44 | { | |
| 45 | - ktime_t now; | |
| 46 | - s64 span; | |
| 47 | + unsigned long long now, span; | |
| 48 | int free, used; | |
| 49 | ||
| 50 | spin_lock(&adapter->qdio_stat_lock); | |
| 51 | - now = ktime_get(); | |
| 52 | - span = ktime_us_delta(now, adapter->req_q_time); | |
| 53 | - free = max(0, atomic_read(&adapter->req_q.count)); | |
| 54 | + now = get_clock_monotonic(); | |
| 55 | + span = (now - adapter->req_q_time) >> 12; | |
| 56 | + free = atomic_read(&adapter->req_q.count); | |
| 57 | used = QDIO_MAX_BUFFERS_PER_Q - free; | |
| 58 | adapter->req_q_util += used * span; | |
| 59 | adapter->req_q_time = now; |