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Re: [Xen-devel] [PATCH] netback: tx stalls with default credit_bytes
| To: | Kirk Allan <kallan@xxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx> |
|---|---|
| Subject: | Re: [Xen-devel] [PATCH] netback: tx stalls with default credit_bytes |
| From: | Keir Fraser <Keir.Fraser@xxxxxxxxxxxx> |
| Date: | Mon, 06 Nov 2006 23:13:05 +0000 |
| Delivery-date: | Mon, 06 Nov 2006 15:13:34 -0800 |
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| Thread-topic: | [Xen-devel] [PATCH] netback: tx stalls with default credit_bytes |
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On 6/11/06 10:50 pm, "Kirk Allan" <kallan@xxxxxxxxxx> wrote: > This situation happens when netif->credit_bytes is using the default of ~0UL, > effectively -1. Once the current tx packet size is greater than the > netif->remaining_credit, transmits will stall until netif->remaining_credit > wraps back to ~0UL in tx_add_credit(). The min(netif->remaining_credit + > netif->credit_bytes, max_burst) has the effect of decrementing > netif->remaining_credit by 1. The min will continually be less than the > current tx packet size until tx_add_credit() is called packet size times which > allows netif->remaining_credit to wrap back to ~0UL. > > The patch splits the min() into two steps to eliminate the case of adding by > -1. Nice catch. Thanks. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel |
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