From: "Björn Töpel" <bjorn.topel@intel.com>
To: "Jakub Kicinski" <kuba@kernel.org>,
"Björn Töpel" <bjorn.topel@gmail.com>
Cc: netdev@vger.kernel.org, bpf@vger.kernel.org,
magnus.karlsson@intel.com, ast@kernel.org, daniel@iogearbox.net,
maciej.fijalkowski@intel.com, sridhar.samudrala@intel.com,
jesse.brandeburg@intel.com, qi.z.zhang@intel.com,
edumazet@google.com, jonathan.lemon@gmail.com,
maximmi@nvidia.com
Subject: Re: [PATCH bpf-next v2 01/10] net: introduce preferred busy-polling
Date: Mon, 16 Nov 2020 18:28:03 +0100 [thread overview]
Message-ID: <b762480b-0eac-e6a5-9bbd-34cc35b43723@intel.com> (raw)
In-Reply-To: <2997d870-09d3-748f-0673-8e2baf7be3fa@intel.com>
On 2020-11-16 17:19, Björn Töpel wrote:
> On 2020-11-16 17:04, Jakub Kicinski wrote:
>> On Mon, 16 Nov 2020 12:04:07 +0100 Björn Töpel wrote:
>>> @@ -6771,6 +6806,19 @@ static int napi_poll(struct napi_struct *n,
>>> struct list_head *repoll)
>>> if (likely(work < weight))
>>> goto out_unlock;
>>> + /* The NAPI context has more processing work, but busy-polling
>>> + * is preferred. Exit early.
>>> + */
>>> + if (napi_prefer_busy_poll(n)) {
>>> + if (napi_complete_done(n, work)) {
>>> + /* If timeout is not set, we need to make sure
>>> + * that the NAPI is re-scheduled.
>>> + */
>>> + napi_schedule(n);
>>> + }
>>> + goto out_unlock;
>>> + }
>>
>> Why is this before the disabled check?
>>
>
> This path is when the budget was exceeded (more work to be done). If the
> prefer flag is set, the napi loop is exited prematurely. We check the
> return value for napi_complete_done, to make sure that there is actually
> a TO value set.
>
> Uhm, maybe I not following what you mean by the "disabled check".
>
Ok, too little coffee.
Yeah, maybe it would make sense to have the disabled check *before* the
"prefer"-checking.
Björn
next prev parent reply other threads:[~2020-11-16 17:28 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-16 11:04 [PATCH bpf-next v2 00/10] Introduce preferred busy-polling Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 01/10] net: introduce " Björn Töpel
2020-11-16 16:04 ` Jakub Kicinski
2020-11-16 16:19 ` Björn Töpel
2020-11-16 17:28 ` Björn Töpel [this message]
2020-11-16 11:04 ` [PATCH bpf-next v2 02/10] net: add SO_BUSY_POLL_BUDGET socket option Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 03/10] xsk: add support for recvmsg() Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 04/10] xsk: check need wakeup flag in sendmsg() Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 05/10] xsk: add busy-poll support for {recv,send}msg() Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 06/10] xsk: propagate napi_id to XDP socket Rx path Björn Töpel
2020-11-16 11:19 ` Tariq Toukan
2020-11-16 11:55 ` Michael S. Tsirkin
2020-11-16 12:01 ` Björn Töpel
2020-11-16 12:42 ` Michael S. Tsirkin
2020-11-16 13:24 ` Björn Töpel
2020-11-16 13:55 ` Michael S. Tsirkin
2020-11-16 17:40 ` Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 07/10] samples/bpf: use recvfrom() in xdpsock/rxdrop Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 08/10] samples/bpf: use recvfrom() in xdpsock/l2fwd Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 09/10] samples/bpf: add busy-poll support to xdpsock Björn Töpel
2020-11-16 11:04 ` [PATCH bpf-next v2 10/10] samples/bpf: add option to set the busy-poll budget Björn Töpel
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