diff options
author | Eliezer Tamir <eliezer.tamir@linux.intel.com> | 2013-07-09 13:09:21 +0300 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2013-07-09 12:33:04 -0700 |
commit | 76b1e9b9813e412bde7446525f6c299803713545 (patch) | |
tree | f062c481d287f1c3b186a9ede8d61abffcf06f8f /include | |
parent | cbf55001b2ddb814329735641be5d29b08c82b08 (diff) | |
download | linux-76b1e9b9813e412bde7446525f6c299803713545.tar.bz2 |
net/fs: change busy poll time accounting
Suggested by Linus:
Changed time accounting for busy-poll:
- Make it microsecond based.
- Use unsigned longs.
- Revert back to use time_after instead of time_in_range.
Reorder poll/select busy loop conditions:
- Clear busy_flag after one time we can't busy-poll.
- Only init busy_end if we actually are going to busy-poll.
Added one more missing need_resched() test.
Signed-off-by: Eliezer Tamir <eliezer.tamir@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r-- | include/net/ll_poll.h | 55 |
1 files changed, 18 insertions, 37 deletions
diff --git a/include/net/ll_poll.h b/include/net/ll_poll.h index f14dd88dafc8..76f034087743 100644 --- a/include/net/ll_poll.h +++ b/include/net/ll_poll.h @@ -47,7 +47,7 @@ static inline bool net_busy_loop_on(void) * we only care that the average is bounded */ #ifdef CONFIG_DEBUG_PREEMPT -static inline u64 busy_loop_sched_clock(void) +static inline u64 busy_loop_us_clock(void) { u64 rc; @@ -55,37 +55,24 @@ static inline u64 busy_loop_sched_clock(void) rc = sched_clock(); preempt_enable_no_resched_notrace(); - return rc; + return rc >> 10; } #else /* CONFIG_DEBUG_PREEMPT */ -static inline u64 busy_loop_sched_clock(void) +static inline u64 busy_loop_us_clock(void) { - return sched_clock(); + return sched_clock() >> 10; } #endif /* CONFIG_DEBUG_PREEMPT */ -/* we don't mind a ~2.5% imprecision so <<10 instead of *1000 - * sk->sk_ll_usec is a u_int so this can't overflow - */ -static inline u64 sk_busy_loop_end_time(struct sock *sk) +static inline unsigned long sk_busy_loop_end_time(struct sock *sk) { - return (u64)ACCESS_ONCE(sk->sk_ll_usec) << 10; + return busy_loop_us_clock() + ACCESS_ONCE(sk->sk_ll_usec); } -/* in poll/select we use the global sysctl_net_ll_poll value - * only call sched_clock() if enabled - */ -static inline u64 busy_loop_end_time(void) -{ - return (u64)ACCESS_ONCE(sysctl_net_ll_poll) << 10; -} - -/* if flag is not set we don't need to know the time - * so we want to avoid a potentially expensive sched_clock() - */ -static inline u64 busy_loop_start_time(unsigned int flag) +/* in poll/select we use the global sysctl_net_ll_poll value */ +static inline unsigned long busy_loop_end_time(void) { - return flag ? busy_loop_sched_clock() : 0; + return busy_loop_us_clock() + ACCESS_ONCE(sysctl_net_ll_poll); } static inline bool sk_can_busy_loop(struct sock *sk) @@ -94,12 +81,12 @@ static inline bool sk_can_busy_loop(struct sock *sk) !need_resched() && !signal_pending(current); } -/* careful! time_in_range64 will evaluate now twice */ -static inline bool busy_loop_range(u64 start_time, u64 run_time) + +static inline bool busy_loop_timeout(unsigned long end_time) { - u64 now = busy_loop_sched_clock(); + unsigned long now = busy_loop_us_clock(); - return time_in_range64(now, start_time, start_time + run_time); + return time_after(now, end_time); } /* when used in sock_poll() nonblock is known at compile time to be true @@ -107,8 +94,7 @@ static inline bool busy_loop_range(u64 start_time, u64 run_time) */ static inline bool sk_busy_loop(struct sock *sk, int nonblock) { - u64 start_time = busy_loop_start_time(!nonblock); - u64 end_time = sk_busy_loop_end_time(sk); + unsigned long end_time = !nonblock ? sk_busy_loop_end_time(sk) : 0; const struct net_device_ops *ops; struct napi_struct *napi; int rc = false; @@ -139,7 +125,7 @@ static inline bool sk_busy_loop(struct sock *sk, int nonblock) LINUX_MIB_LOWLATENCYRXPACKETS, rc); } while (!nonblock && skb_queue_empty(&sk->sk_receive_queue) && - busy_loop_range(start_time, end_time)); + !need_resched() && !busy_loop_timeout(end_time)); rc = !skb_queue_empty(&sk->sk_receive_queue); out: @@ -165,12 +151,7 @@ static inline unsigned long net_busy_loop_on(void) return 0; } -static inline u64 busy_loop_start_time(unsigned int flag) -{ - return 0; -} - -static inline u64 busy_loop_end_time(void) +static inline unsigned long busy_loop_end_time(void) { return 0; } @@ -193,9 +174,9 @@ static inline void sk_mark_ll(struct sock *sk, struct sk_buff *skb) { } -static inline bool busy_loop_range(u64 start_time, u64 run_time) +static inline bool busy_loop_timeout(unsigned long end_time) { - return false; + return true; } #endif /* CONFIG_NET_LL_RX_POLL */ |