Re: [MAINLINE 2/2] rds: ib: Add Dynamic Interrupt Moderation to CQs

[Zhu Yanjun <yanjun.zhu@linux.dev>]

在 2024/9/20 17:42, Haakon Bugge 写道:
> 
> 
>> On 20 Sep 2024, at 09:47, Zhu Yanjun <yanjun.zhu@linux.dev> wrote:
>>
>> 在 2024/9/18 16:35, Håkon Bugge 写道:
>>> With the support from ib_core to use Dynamic Interrupt Moderation
>>> (DIM) from legacy ULPs, which uses ib_create_cq(), we enable that
>>> feature for the receive and send CQs in RDS.
>>
>> Hi, Haakon
>>
>> I am interested in this patch series. I just wonder if the performance of rds is increased after DIM is used in legacy ULPs?
>> That is, is there any benefit to legacy ULPs after DIM is used?
>>
>> Do you have any test results about this DIM?
> 
> Yes, please see the cover letter of this commit.

Which Oracle Linux distro includes this feature?
And what is the kernel version?

Zhu Yanjun

> 
> 
> Thxs, Håkon
> 
>>
>> Thanks,
>> Zhu Yanjun
>>
>>> A set of rds-stress runs have been done. bcopy read + write for
>>> payload 8448 and 16640 bytes and ack/req of 256 bytes. Number of QPs
>>> varies from 8 to 128, number of threads (i.e. rds-stress processes)
>>> from one to 16 and a depth of four. A limit has been applied such that
>>> the number of processes times the number of QPs never exceeds 128. All
>>> in all, 61 rds-stress runs.
>>> For brevity, only the rows showing a +/- 3% deviation or larger from
>>> base is listed. The geometric mean of the ratios (IOPS_test /
>>> IOPS_base) is calculated for all 61 runs, and that gives the best
>>> possible "average" impact of the commits.
>>> In the following, "base" is v6.11-rc7. "test" is the same
>>> kernel with the following two commits:
>>>         * rds: ib: Add Dynamic Interrupt Moderation to CQs (this commit)
>>>         * RDMA/core: Enable legacy ULPs to use RDMA DIM
>>> This is executed between two X8-2 with CX-5 using fw 16.35.3502. These
>>> BM systems were instantiated with one VF, which were used for the
>>> test:
>>>                                   base     test
>>>     ACK    REQ  QPS  THR  DEP     IOPS     IOPS  Percent
>>>     256   8448    8    1    4   634463   658162      3.7
>>>     256   8448    8    2    4   862648   997358     15.6
>>>     256   8448    8    4    4   950458  1113991     17.2
>>>     256   8448    8    8    4   932120  1127024     20.9
>>>     256   8448    8   16    4   944977  1133885     20.0
>>>    8448    256    8    2    4   858663   975563     13.6
>>>    8448    256    8    4    4   934884  1098854     17.5
>>>    8448    256    8    8    4   928247  1116015     20.2
>>>    8448    256    8   16    4   938864  1123455     19.7
>>>     256   8448   64    1    4   965985   918445     -4.9
>>>    8448    256   64    1    4   963280   918239     -4.7
>>>     256  16640    8    2    4   544670   582330      6.9
>>>     256  16640    8    4    4   554873   597553      7.7
>>>     256  16640    8    8    4   551799   597479      8.3
>>>     256  16640    8   16    4   553041   597898      8.1
>>>   16640    256    8    2    4   544644   578331      6.2
>>>   16640    256    8    4    4   553944   594627      7.3
>>>   16640    256    8    8    4   551388   594737      7.9
>>>   16640    256    8   16    4   552986   596581      7.9
>>> Geometric mean of ratios: 1.03
>>> Signed-off-by: Håkon Bugge <haakon.bugge@oracle.com>
>>> ---
>>>   net/rds/ib_cm.c | 10 ++++++++++
>>>   1 file changed, 10 insertions(+)
>>> diff --git a/net/rds/ib_cm.c b/net/rds/ib_cm.c
>>> index 26b069e1999df..79603d86b6c02 100644
>>> --- a/net/rds/ib_cm.c
>>> +++ b/net/rds/ib_cm.c
>>> @@ -259,6 +259,7 @@ static void rds_ib_cq_comp_handler_recv(struct ib_cq *cq, void *context)
>>>   static void poll_scq(struct rds_ib_connection *ic, struct ib_cq *cq,
>>>        struct ib_wc *wcs)
>>>   {
>>> + int ncompleted = 0;
>>>    int nr, i;
>>>    struct ib_wc *wc;
>>>   @@ -276,7 +277,10 @@ static void poll_scq(struct rds_ib_connection *ic, struct ib_cq *cq,
>>>    rds_ib_mr_cqe_handler(ic, wc);
>>>      }
>>> + ncompleted += nr;
>>>    }
>>> + if (cq->dim)
>>> + rdma_dim(cq->dim, ncompleted);
>>>   }
>>>     static void rds_ib_tasklet_fn_send(unsigned long data)
>>> @@ -304,6 +308,7 @@ static void poll_rcq(struct rds_ib_connection *ic, struct ib_cq *cq,
>>>        struct ib_wc *wcs,
>>>        struct rds_ib_ack_state *ack_state)
>>>   {
>>> + int ncompleted = 0;
>>>    int nr, i;
>>>    struct ib_wc *wc;
>>>   @@ -316,7 +321,10 @@ static void poll_rcq(struct rds_ib_connection *ic, struct ib_cq *cq,
>>>      rds_ib_recv_cqe_handler(ic, wc, ack_state);
>>>    }
>>> + ncompleted += nr;
>>>    }
>>> + if (cq->dim)
>>> + rdma_dim(cq->dim, ncompleted);
>>>   }
>>>     static void rds_ib_tasklet_fn_recv(unsigned long data)
>>> @@ -542,6 +550,7 @@ static int rds_ib_setup_qp(struct rds_connection *conn)
>>>    ic->i_scq_vector = ibdev_get_unused_vector(rds_ibdev);
>>>    cq_attr.cqe = ic->i_send_ring.w_nr + fr_queue_space + 1;
>>>    cq_attr.comp_vector = ic->i_scq_vector;
>>> + cq_attr.flags |= IB_CQ_MODERATE;
>>>    ic->i_send_cq = ib_create_cq(dev, rds_ib_cq_comp_handler_send,
>>>        rds_ib_cq_event_handler, conn,
>>>        &cq_attr);
>>> @@ -556,6 +565,7 @@ static int rds_ib_setup_qp(struct rds_connection *conn)
>>>    ic->i_rcq_vector = ibdev_get_unused_vector(rds_ibdev);
>>>    cq_attr.cqe = ic->i_recv_ring.w_nr;
>>>    cq_attr.comp_vector = ic->i_rcq_vector;
>>> + cq_attr.flags |= IB_CQ_MODERATE;
>>>    ic->i_recv_cq = ib_create_cq(dev, rds_ib_cq_comp_handler_recv,
>>>        rds_ib_cq_event_handler, conn,
>>>        &cq_attr);
>>
>