This puts tasks submitted to the SDIO workqueue at the head of the queue
and runs them immediately. This gets higher RX throughput with the SDIO
bus.
This was originally submitted as [1]. The original author Wright Feng
reports
> throughput result with 43455(11ac) on 1 core 1.6 Ghz platform is
> Without WQ_HIGGPRI TX/RX: 293/301 (mbps)
> With WQ_HIGHPRI TX/RX: 293/321 (mbps)
I tested this with a 43364(11bgn) on a 1 core 800 MHz platform and got
Without WQ_HIGHPRI TX/RX: 16/19 (Mbits/sec)
With WQ_HIGHPRI TX/RX: 24/20 (MBits/sec)
[1] https://lore.kernel.org/linux-wireless/[email protected]/
Signed-off-by: Sean Anderson <[email protected]>
---
drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
index 97ee9e2e2e35..5e10176c6c7e 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
@@ -4442,7 +4442,7 @@ struct brcmf_sdio *brcmf_sdio_probe(struct brcmf_sdio_dev *sdiodev)
bus->tx_seq = SDPCM_SEQ_WRAP - 1;
/* single-threaded workqueue */
- wq = alloc_ordered_workqueue("brcmf_wq/%s", WQ_MEM_RECLAIM,
+ wq = alloc_ordered_workqueue("brcmf_wq/%s", WQ_MEM_RECLAIM | WQ_HIGHPRI,
dev_name(&sdiodev->func1->dev));
if (!wq) {
brcmf_err("insufficient memory to create txworkqueue\n");
--
2.25.1
ping?
On 8/2/21 1:09 PM, Sean Anderson wrote:
> This puts tasks submitted to the SDIO workqueue at the head of the queue
> and runs them immediately. This gets higher RX throughput with the SDIO
> bus.
>
> This was originally submitted as [1]. The original author Wright Feng
> reports
>
>> throughput result with 43455(11ac) on 1 core 1.6 Ghz platform is
>> Without WQ_HIGGPRI TX/RX: 293/301 (mbps)
>> With WQ_HIGHPRI TX/RX: 293/321 (mbps)
>
> I tested this with a 43364(11bgn) on a 1 core 800 MHz platform and got
> Without WQ_HIGHPRI TX/RX: 16/19 (Mbits/sec)
> With WQ_HIGHPRI TX/RX: 24/20 (MBits/sec)
>
> [1] https://lore.kernel.org/linux-wireless/[email protected]/
>
> Signed-off-by: Sean Anderson <[email protected]>
> ---
>
> drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> index 97ee9e2e2e35..5e10176c6c7e 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> @@ -4442,7 +4442,7 @@ struct brcmf_sdio *brcmf_sdio_probe(struct brcmf_sdio_dev *sdiodev)
> bus->tx_seq = SDPCM_SEQ_WRAP - 1;
>
> /* single-threaded workqueue */
> - wq = alloc_ordered_workqueue("brcmf_wq/%s", WQ_MEM_RECLAIM,
> + wq = alloc_ordered_workqueue("brcmf_wq/%s", WQ_MEM_RECLAIM | WQ_HIGHPRI,
> dev_name(&sdiodev->func1->dev));
> if (!wq) {
> brcmf_err("insufficient memory to create txworkqueue\n");
>
On August 17, 2021 6:50:50 PM Sean Anderson <[email protected]> wrote:
> ping?
Good idea to ping with a top-level post :-p
>
>
> On 8/2/21 1:09 PM, Sean Anderson wrote:
>> This puts tasks submitted to the SDIO workqueue at the head of the queue
>> and runs them immediately. This gets higher RX throughput with the SDIO
>> bus.
>>
>> This was originally submitted as [1]. The original author Wright Feng
>> reports
>>
>>> throughput result with 43455(11ac) on 1 core 1.6 Ghz platform is
>>> Without WQ_HIGGPRI TX/RX: 293/301 (mbps)
>>> With WQ_HIGHPRI TX/RX: 293/321 (mbps)
>>
>> I tested this with a 43364(11bgn) on a 1 core 800 MHz platform and got
>> Without WQ_HIGHPRI TX/RX: 16/19 (Mbits/sec)
>> With WQ_HIGHPRI TX/RX: 24/20 (MBits/sec)
>>
>> [1]
>> https://lore.kernel.org/linux-wireless/[email protected]/
While I understand the obvious gain it seems like a wrong move to me. What
if all workqueues in the kernel would start using this flag? I bet the gain
above would be negated and all are equal in the eyes of .. the kernel
Regards,
Arend
On 8/17/21 1:17 PM, Arend van Spriel wrote:
> On August 17, 2021 6:50:50 PM Sean Anderson <[email protected]> wrote:
>
>> ping?
>
> Good idea to ping with a top-level post :-p
Sorry, I'm not subscribed to this list; did I mess up the list/CC for the original?
>
>>
>>
>> On 8/2/21 1:09 PM, Sean Anderson wrote:
>>> This puts tasks submitted to the SDIO workqueue at the head of the queue
>>> and runs them immediately. This gets higher RX throughput with the SDIO
>>> bus.
>>>
>>> This was originally submitted as [1]. The original author Wright Feng
>>> reports
>>>
>>>> throughput result with 43455(11ac) on 1 core 1.6 Ghz platform is
>>>> Without WQ_HIGGPRI TX/RX: 293/301 (mbps)
>>>> With WQ_HIGHPRI TX/RX: 293/321 (mbps)
>>>
>>> I tested this with a 43364(11bgn) on a 1 core 800 MHz platform and got
>>> Without WQ_HIGHPRI TX/RX: 16/19 (Mbits/sec)
>>> With WQ_HIGHPRI TX/RX: 24/20 (MBits/sec)
>>>
>>> [1] https://lore.kernel.org/linux-wireless/[email protected]/
>
> While I understand the obvious gain it seems like a wrong move to me. What if all workqueues in the kernel would start using this flag? I bet the gain above would be negated and all are equal in the eyes of .. the kernel
Is there an official policy on what counts as high-priority? Using some
very-scientific methodology [1], it seems like most high-priority
workqueues are in drivers/net and fs. Making these queues high-priority
seems to be commonplace. For example, in fe101716c7c9 ("rtw88: replace
tx tasklet with work queue"), Po-Hao Huang remarks:
> Since throughput is delay-sensitive in most cases, we allocate a
> dedicated, high priority wq for our needs.
which is effectively the same rationale as this patch. At least for my
application, network transfer speed is one of the most important
performance metrics.
The original patch got the following feedback [2] from Kalle Valo:
> Why would someone want to disable this? Like in patch 2, please avoid
> adding new module parameters as much as possible.
so for this patch I just made the workqueue high-priority
unconditionally.
--Sean
[1] git grep -l WQ_HIGHPRI | cut -f 1,2 -d / | uniq -c | sort -n
[2] https://lore.kernel.org/linux-wireless/[email protected]/
Hello,
On Tue, Aug 17, 2021 at 02:21:55PM -0400, Sean Anderson wrote:
> > While I understand the obvious gain it seems like a wrong move to me. What if all workqueues in the kernel would start using this flag? I bet the gain above would be negated and all are equal in the eyes of .. the kernel
>
> Is there an official policy on what counts as high-priority? Using some
> very-scientific methodology [1], it seems like most high-priority
> workqueues are in drivers/net and fs. Making these queues high-priority
> seems to be commonplace. For example, in fe101716c7c9 ("rtw88: replace
> tx tasklet with work queue"), Po-Hao Huang remarks:
I think this is actually a good candidate for HIGHPRI. As you noted, stuff
which interacts with hardware in latency sensitive manner with impact on
observable performance is one of the common use cases. The alternatives
would be doing it from hard/softirqs which are higher priorities anyway.
Thanks.
--
tejun
On August 17, 2021 8:28:23 PM Tejun Heo <[email protected]> wrote:
> Hello,
>
> On Tue, Aug 17, 2021 at 02:21:55PM -0400, Sean Anderson wrote:
>>> While I understand the obvious gain it seems like a wrong move to me. What
>>> if all workqueues in the kernel would start using this flag? I bet the gain
>>> above would be negated and all are equal in the eyes of .. the kernel
>>
>> Is there an official policy on what counts as high-priority? Using some
>> very-scientific methodology [1], it seems like most high-priority
>> workqueues are in drivers/net and fs. Making these queues high-priority
>> seems to be commonplace. For example, in fe101716c7c9 ("rtw88: replace
>> tx tasklet with work queue"), Po-Hao Huang remarks:
>
> I think this is actually a good candidate for HIGHPRI. As you noted, stuff
> which interacts with hardware in latency sensitive manner with impact on
> observable performance is one of the common use cases. The alternatives
> would be doing it from hard/softirqs which are higher priorities anyway.
Hi, Tejun
Thanks for the explanation.
Regards,
Arend
On August 2, 2021 7:11:12 PM Sean Anderson <[email protected]> wrote:
> This puts tasks submitted to the SDIO workqueue at the head of the queue
> and runs them immediately. This gets higher RX throughput with the SDIO
> bus.
>
> This was originally submitted as [1]. The original author Wright Feng
> reports
>
>> throughput result with 43455(11ac) on 1 core 1.6 Ghz platform is
>> Without WQ_HIGGPRI TX/RX: 293/301 (mbps)
>> With WQ_HIGHPRI TX/RX: 293/321 (mbps)
>
> I tested this with a 43364(11bgn) on a 1 core 800 MHz platform and got
> Without WQ_HIGHPRI TX/RX: 16/19 (Mbits/sec)
> With WQ_HIGHPRI TX/RX: 24/20 (MBits/sec)
>
> [1]
> https://lore.kernel.org/linux-wireless/[email protected]/
Not sure if Wright Feng needs to be attributed as you clearly had a good
look at his patch and the discussion related to it. You can add my ...
Reviewed-by: Arend van Spriel <[email protected]>
> Signed-off-by: Sean Anderson <[email protected]>
> ---
>
> drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Sean Anderson <[email protected]> wrote:
> This puts tasks submitted to the SDIO workqueue at the head of the queue
> and runs them immediately. This gets higher RX throughput with the SDIO
> bus.
>
> This was originally submitted as [1]. The original author Wright Feng
> reports
>
> > throughput result with 43455(11ac) on 1 core 1.6 Ghz platform is
> > Without WQ_HIGGPRI TX/RX: 293/301 (mbps)
> > With WQ_HIGHPRI TX/RX: 293/321 (mbps)
>
> I tested this with a 43364(11bgn) on a 1 core 800 MHz platform and got
> Without WQ_HIGHPRI TX/RX: 16/19 (Mbits/sec)
> With WQ_HIGHPRI TX/RX: 24/20 (MBits/sec)
>
> [1] https://lore.kernel.org/linux-wireless/[email protected]/
>
> Signed-off-by: Sean Anderson <[email protected]>
> Reviewed-by: Arend van Spriel <[email protected]>
Patch applied to wireless-drivers-next.git, thanks.
41b637bac0b0 brcmfmac: Set SDIO workqueue as WQ_HIGHPRI
--
https://patchwork.kernel.org/project/linux-wireless/patch/[email protected]/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches