Re: [PATCH] hw/nvme: add trace events for ioeventfd

[Klaus Jensen <its@irrelevant.dk>]

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On Jul 20 10:47, Jinhao Fan wrote:
> at 10:41 PM, Jinhao Fan <fanjinhao21s@ict.ac.cn> wrote:
> 
> > at 1:34 PM, Klaus Jensen <its@irrelevant.dk> wrote:
> > 
> >> From: Klaus Jensen <k.jensen@samsung.com>
> >> 
> >> While testing Jinhaos ioeventfd patch I found it useful with a couple of
> >> additional trace events since we no longer see the mmio events.
> >> 
> >> Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
> >> ---
> >> hw/nvme/ctrl.c       | 8 ++++++++
> >> hw/nvme/trace-events | 4 ++++
> >> 2 files changed, 12 insertions(+)
> >> 
> >> diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
> >> index 533ad14e7a61..09725ec49c5d 100644
> >> --- a/hw/nvme/ctrl.c
> >> +++ b/hw/nvme/ctrl.c
> >> @@ -1346,6 +1346,8 @@ static void nvme_post_cqes(void *opaque)
> >>    bool pending = cq->head != cq->tail;
> >>    int ret;
> >> 
> >> +    trace_pci_nvme_post_cqes(cq->cqid);
> >> +
> >>    QTAILQ_FOREACH_SAFE(req, &cq->req_list, entry, next) {
> >>        NvmeSQueue *sq;
> >>        hwaddr addr;
> >> @@ -4238,6 +4240,8 @@ static void nvme_cq_notifier(EventNotifier *e)
> >>    NvmeCQueue *cq = container_of(e, NvmeCQueue, notifier);
> >>    NvmeCtrl *n = cq->ctrl;
> >> 
> >> +    trace_pci_nvme_cq_notify(cq->cqid);
> >> +
> >>    event_notifier_test_and_clear(&cq->notifier);
> >> 
> >>    nvme_update_cq_head(cq);
> >> @@ -4275,6 +4279,8 @@ static void nvme_sq_notifier(EventNotifier *e)
> >> {
> >>    NvmeSQueue *sq = container_of(e, NvmeSQueue, notifier);
> >> 
> >> +    trace_pci_nvme_sq_notify(sq->sqid);
> >> +
> >>    event_notifier_test_and_clear(&sq->notifier);
> >> 
> >>    nvme_process_sq(sq);
> >> @@ -6240,6 +6246,8 @@ static void nvme_process_sq(void *opaque)
> >>    NvmeCtrl *n = sq->ctrl;
> >>    NvmeCQueue *cq = n->cq[sq->cqid];
> >> 
> >> +    trace_pci_nvme_process_sq(sq->sqid);
> >> +
> >>    uint16_t status;
> >>    hwaddr addr;
> >>    NvmeCmd cmd;
> >> diff --git a/hw/nvme/trace-events b/hw/nvme/trace-events
> >> index fccb79f48973..45dd708bd2fa 100644
> >> --- a/hw/nvme/trace-events
> >> +++ b/hw/nvme/trace-events
> >> @@ -104,6 +104,10 @@ pci_nvme_mmio_shutdown_set(void) "shutdown bit set"
> >> pci_nvme_mmio_shutdown_cleared(void) "shutdown bit cleared"
> >> pci_nvme_shadow_doorbell_cq(uint16_t cqid, uint16_t new_shadow_doorbell) "cqid %"PRIu16" new_shadow_doorbell %"PRIu16""
> >> pci_nvme_shadow_doorbell_sq(uint16_t sqid, uint16_t new_shadow_doorbell) "sqid %"PRIu16" new_shadow_doorbell %"PRIu16""
> >> +pci_nvme_sq_notify(uint16_t sqid) "sqid %"PRIu16""
> >> +pci_nvme_cq_notify(uint16_t cqid) "cqid %"PRIu16""
> >> +pci_nvme_process_sq(uint16_t sqid) "sqid %"PRIu16""
> >> +pci_nvme_post_cqes(uint16_t cqid) "cqid %"PRIu16""
> >> pci_nvme_open_zone(uint64_t slba, uint32_t zone_idx, int all) "open zone, slba=%"PRIu64", idx=%"PRIu32", all=%"PRIi32""
> >> pci_nvme_close_zone(uint64_t slba, uint32_t zone_idx, int all) "close zone, slba=%"PRIu64", idx=%"PRIu32", all=%"PRIi32""
> >> pci_nvme_finish_zone(uint64_t slba, uint32_t zone_idx, int all) "finish zone, slba=%"PRIu64", idx=%"PRIu32", all=%"PRIi32""
> >> -- 
> >> 2.36.1
> > 
> > I agree on the addition of SQ and CQ notify trace events. But what is the
> > purpose for adding tracepoints for nvme_process_sq and nvme_post_cqes?
> 
> I realized these two events are useful when debugging iothread support. We
> are processing sqe and cqe’s in a batch in nvme_process_sq and
> nvme_post_cqes. It is important to mark the beginning of the batch.

If you can add your Reviewed-by here, I can queue it up ;)

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