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Commit a0bf4c6

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ON-16915: Reduce chance of overflow with shared queue
This aligns sizing of the kernel EVQ with the number of outstanding buffers from userspace. A follow up change will properly fix this by linking buffer post to EVQ space.
1 parent 4087b64 commit a0bf4c6

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2 files changed

+13
-3
lines changed

2 files changed

+13
-3
lines changed

‎src/lib/ciul/efct_ubufs.c‎

Lines changed: 7 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -557,8 +557,13 @@ int efct_ubufs_init(ef_vi* vi, ef_pd* pd, ef_driver_handle pd_dh)
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}
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/* TODO ON-16686 get this limit from the design parameter DP_RX_BUFFER_FIFO_SIZE,
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* perhaps allow configuration to a smaller value to reduce working set */
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ubufs->nic_fifo_limit = 128;
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* perhaps allow configuration to a smaller value to reduce working set.
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* The current value here is selected such that completions for a full
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* set of buffers will not exceed the kernel EVQ size. Overflow is still
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* possible if the kernel poll does not keep up as the user space code
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* judges fill level based on RX buffer fill, so the hw fifo can be empty
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* without the kernel EVQ having been drained. */
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ubufs->nic_fifo_limit = 64;
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ubufs->pd = pd;
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ubufs->pd_dh = pd_dh;
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ubufs->is_shrub_token_set = false;

‎src/lib/efhw/ef10ct/aux_ef10ct.c‎

Lines changed: 6 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -335,7 +335,12 @@ static int ef10ct_nic_create_shared_evq(struct efhw_nic *nic, int shared_ix,
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{
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struct efhw_nic_ef10ct *ef10ct = nic->arch_extra;
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struct efhw_nic_ef10ct_evq *ef10ct_evq;
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uint page_order = 0; /* TODO: What should the size be? */
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/* For the queue that just receives flushes we don't need much space, so
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* just use minimum size. At the moment we don't have a way to sync RX
340+
* buffer posting with EVQ poll, so we need to size the EVQ to cope with the
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* maximum number of outstanding RX events for queues that handle RX evs.
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* We set the queue as big as possible here. */
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uint page_order = shared_ix == EF10CT_SHARED_NO_RX_EVS ? 0 : 6;
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int evq_id, rc, evq_num;
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struct ef10ct_shared_kernel_evq *shared_evq = &ef10ct->shared[shared_ix];
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irq_handler_t handler;

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