| Message ID | 4F7D7464.7040503@gmail.com |
|---|---|
| State | Rejected, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Li Yu <raise.sail@gmail.com> Date: Thu, 05 Apr 2012 18:31:00 +0800 > > We encountered a buggy NIC driver or hardware/firmware, it keeps > non-zero constant skb->rxhash for long time, so if we enabled RPS, > the targeted CPU keeps same for long time too. > > This patch introduces a sysctl switch to workaround for such problem, > if the switch was on, RPS core discards the skb->rxhash that is > computed by NIC hardware. > > Hope this patch also can help others, thanks. > > Signed-off-by Li Yu <bingtian.ly@taobao.com> No way, we fix the drivers not add workarounds like this. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 2012-04-05 at 18:31 +0800, Li Yu wrote: > We encountered a buggy NIC driver or hardware/firmware, it keeps > non-zero constant skb->rxhash for long time, so if we enabled RPS, > the targeted CPU keeps same for long time too. > > This patch introduces a sysctl switch to workaround for such problem, > if the switch was on, RPS core discards the skb->rxhash that is > computed by NIC hardware. > > Hope this patch also can help others, thanks. Really ? to disable this driver rxhash, you should try : ethtool -K eth0 rxhash off -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
于 2012年04月05日 19:07, Eric Dumazet 写道: > On Thu, 2012-04-05 at 18:31 +0800, Li Yu wrote: >> We encountered a buggy NIC driver or hardware/firmware, it keeps >> non-zero constant skb->rxhash for long time, so if we enabled RPS, >> the targeted CPU keeps same for long time too. >> >> This patch introduces a sysctl switch to workaround for such problem, >> if the switch was on, RPS core discards the skb->rxhash that is >> computed by NIC hardware. >> >> Hope this patch also can help others, thanks. > > Really ? > > to disable this driver rxhash, you should try : > > ethtool -K eth0 rxhash off > > Great! I really did not know this new option ago, and wrote a kprobe workaround module. It seem that ethtool 2.6.39 have such support at least. Thank you very much! Yu > > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 192250b..4c28ce0 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -628,9 +628,13 @@ extern unsigned int skb_find_text(struct sk_buff *skb, unsigned int from, unsigned int to, struct ts_config *config, struct ts_state *state); +extern int rps_workaround_buggy_driver; extern void __skb_get_rxhash(struct sk_buff *skb); static inline __u32 skb_get_rxhash(struct sk_buff *skb) { + if (unlikely(rps_workaround_buggy_driver)) + skb->rxhash = 0; + if (!skb->rxhash) __skb_get_rxhash(skb); diff --git a/net/core/dev.c b/net/core/dev.c index 723a406..9d1e728 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -176,6 +176,8 @@ #define PTYPE_HASH_SIZE (16) #define PTYPE_HASH_MASK (PTYPE_HASH_SIZE - 1) +int rps_workaround_buggy_driver = 0; + static DEFINE_SPINLOCK(ptype_lock); static struct list_head ptype_base[PTYPE_HASH_SIZE] __read_mostly; static struct list_head ptype_all __read_mostly; /* Taps */ diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index 0c28508..065ea7c 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -172,6 +172,13 @@ static struct ctl_table net_core_table[] = { .mode = 0644, .proc_handler = rps_sock_flow_sysctl }, + { + .procname = "rps_workaround_buggy_driver", + .data = &rps_workaround_buggy_driver, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec + }, #endif #endif /* CONFIG_NET */ {