* [dpdk-dev] [PATCH] event/octeontx2: remove WFE from dualslot dequeue
@ 2020-02-14 6:45 pbhagavatula
2020-02-15 5:56 ` Gavin Hu
0 siblings, 1 reply; 5+ messages in thread
From: pbhagavatula @ 2020-02-14 6:45 UTC (permalink / raw)
To: jerinj, Pavan Nikhilesh; +Cc: gavin.hu, dev
From: Pavan Nikhilesh <pbhagavatula@marvell.com>
Each workslot is always bound to a specific lcore there is no multi-core
contention to cause cache trashing as a result it is safe to remove the
WFE. Also, in dual workslot dequeue work will mostlikely be available on
the pair workslot making WFE impractical.
Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
---
Also, this in-turn reduces the branch misses
Before:
0 arm_spe_0/ts_enable=1,pct_enable=1,pa_enable=1,branch_filter=1,jitter=1,min_latency=0/
0 dummy:u
0 llc-miss
0 tlb-miss
853 branch-miss
0 remote-access
0 l1d-miss
After:
0 arm_spe_0/ts_enable=1,pct_enable=1,pa_enable=1,branch_filter=1,jitter=1,min_latency=0/
0 dummy:u
0 llc-miss
0 tlb-miss
250 branch-miss
0 remote-access
0 l1d-miss
WFE Data:
0x4C40 - WFI_WFE_WAIT_CYCLES - Number of cycles waiting at a WFI or WFE instruction.
- WFE Cycles before the patch for Dual workslot
#perf stat -C 20 -e r4C40 sleep 1
Performance counter stats for 'CPU(s) 20':
264 r4C40
1.002494168 seconds time elapsed
- WFE Cycles for single workslot
#perf stat -C 20 -e r4C40 sleep 1
Performance counter stats for 'CPU(s) 20':
908,778,351 r4C40
1.002598253 seconds time elapsed
drivers/event/octeontx2/otx2_worker_dual.h | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/drivers/event/octeontx2/otx2_worker_dual.h b/drivers/event/octeontx2/otx2_worker_dual.h
index 5134e3d52..c88420eb4 100644
--- a/drivers/event/octeontx2/otx2_worker_dual.h
+++ b/drivers/event/octeontx2/otx2_worker_dual.h
@@ -29,11 +29,7 @@ otx2_ssogws_dual_get_work(struct otx2_ssogws_state *ws,
rte_prefetch_non_temporal(lookup_mem);
#ifdef RTE_ARCH_ARM64
asm volatile(
- " ldr %[tag], [%[tag_loc]] \n"
- " ldr %[wqp], [%[wqp_loc]] \n"
- " tbz %[tag], 63, done%= \n"
- " sevl \n"
- "rty%=: wfe \n"
+ "rty%=: \n"
" ldr %[tag], [%[tag_loc]] \n"
" ldr %[wqp], [%[wqp_loc]] \n"
" tbnz %[tag], 63, rty%= \n"
--
2.17.1
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [dpdk-dev] [PATCH] event/octeontx2: remove WFE from dualslot dequeue
2020-02-14 6:45 [dpdk-dev] [PATCH] event/octeontx2: remove WFE from dualslot dequeue pbhagavatula
@ 2020-02-15 5:56 ` Gavin Hu
2020-02-15 9:43 ` Pavan Nikhilesh Bhagavatula
0 siblings, 1 reply; 5+ messages in thread
From: Gavin Hu @ 2020-02-15 5:56 UTC (permalink / raw)
To: pbhagavatula, jerinj; +Cc: dev, nd
Hi Pavan,
> -----Original Message-----
> From: pbhagavatula@marvell.com <pbhagavatula@marvell.com>
> Sent: Friday, February 14, 2020 2:45 PM
> To: jerinj@marvell.com; Pavan Nikhilesh <pbhagavatula@marvell.com>
> Cc: Gavin Hu <Gavin.Hu@arm.com>; dev@dpdk.org
> Subject: [dpdk-dev] [PATCH] event/octeontx2: remove WFE from dualslot
> dequeue
>
> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
>
> Each workslot is always bound to a specific lcore there is no multi-core
> contention to cause cache trashing as a result it is safe to remove the
> WFE. Also, in dual workslot dequeue work will mostlikely be available on
> the pair workslot making WFE impractical.
Does SSO still signal EVENTI to exit from WFE? Then the core ignore it?
Can this be disabled as WFE is removed?
>
> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
> ---
>
> Also, this in-turn reduces the branch misses
>
> Before:
> 0
> arm_spe_0/ts_enable=1,pct_enable=1,pa_enable=1,branch_filter=1,jitter=1,
> min_latency=0/
> 0 dummy:u
> 0 llc-miss
> 0 tlb-miss
> 853 branch-miss
> 0 remote-access
> 0 l1d-miss
>
> After:
> 0
> arm_spe_0/ts_enable=1,pct_enable=1,pa_enable=1,branch_filter=1,jitter=1,
> min_latency=0/
> 0 dummy:u
> 0 llc-miss
> 0 tlb-miss
> 250 branch-miss
> 0 remote-access
> 0 l1d-miss
>
> WFE Data:
>
> 0x4C40 - WFI_WFE_WAIT_CYCLES - Number of cycles waiting at a WFI or
> WFE instruction.
>
> - WFE Cycles before the patch for Dual workslot
> #perf stat -C 20 -e r4C40 sleep 1
> Performance counter stats for 'CPU(s) 20':
>
> 264 r4C40
> 1.002494168 seconds time elapsed
>
> - WFE Cycles for single workslot
> #perf stat -C 20 -e r4C40 sleep 1
> Performance counter stats for 'CPU(s) 20':
>
> 908,778,351 r4C40
> 1.002598253 seconds time elapsed
>
> drivers/event/octeontx2/otx2_worker_dual.h | 6 +-----
> 1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/drivers/event/octeontx2/otx2_worker_dual.h
> b/drivers/event/octeontx2/otx2_worker_dual.h
> index 5134e3d52..c88420eb4 100644
> --- a/drivers/event/octeontx2/otx2_worker_dual.h
> +++ b/drivers/event/octeontx2/otx2_worker_dual.h
> @@ -29,11 +29,7 @@ otx2_ssogws_dual_get_work(struct
> otx2_ssogws_state *ws,
> rte_prefetch_non_temporal(lookup_mem);
> #ifdef RTE_ARCH_ARM64
> asm volatile(
> - " ldr %[tag], [%[tag_loc]] \n"
> - " ldr %[wqp], [%[wqp_loc]] \n"
> - " tbz %[tag], 63, done%= \n"
> - " sevl \n"
> - "rty%=: wfe \n"
> + "rty%=: \n"
> " ldr %[tag], [%[tag_loc]] \n"
> " ldr %[wqp], [%[wqp_loc]] \n"
> " tbnz %[tag], 63, rty%= \n"
> --
> 2.17.1
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [dpdk-dev] [PATCH] event/octeontx2: remove WFE from dualslot dequeue
2020-02-15 5:56 ` Gavin Hu
@ 2020-02-15 9:43 ` Pavan Nikhilesh Bhagavatula
2020-02-15 12:23 ` Gavin Hu
0 siblings, 1 reply; 5+ messages in thread
From: Pavan Nikhilesh Bhagavatula @ 2020-02-15 9:43 UTC (permalink / raw)
To: Gavin Hu, Jerin Jacob Kollanukkaran; +Cc: dev, nd
Hi Gavin,
>Hi Pavan,
>
>> -----Original Message-----
>> From: pbhagavatula@marvell.com <pbhagavatula@marvell.com>
>> Sent: Friday, February 14, 2020 2:45 PM
>> To: jerinj@marvell.com; Pavan Nikhilesh
><pbhagavatula@marvell.com>
>> Cc: Gavin Hu <Gavin.Hu@arm.com>; dev@dpdk.org
>> Subject: [dpdk-dev] [PATCH] event/octeontx2: remove WFE from
>dualslot
>> dequeue
>>
>> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
>>
>> Each workslot is always bound to a specific lcore there is no multi-core
>> contention to cause cache trashing as a result it is safe to remove the
>> WFE. Also, in dual workslot dequeue work will mostlikely be available
>on
>> the pair workslot making WFE impractical.
>
>Does SSO still signal EVENTI to exit from WFE? Then the core ignore it?
All transactions on SSO bus take the core out of WFE.
>Can this be disabled as WFE is removed?
This can't be disabled.
>
>>
>> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
>> ---
>>
>> Also, this in-turn reduces the branch misses
>>
>> Before:
>> 0
>>
>arm_spe_0/ts_enable=1,pct_enable=1,pa_enable=1,branch_filter=1,jit
>ter=1,
>> min_latency=0/
>> 0 dummy:u
>> 0 llc-miss
>> 0 tlb-miss
>> 853 branch-miss
>> 0 remote-access
>> 0 l1d-miss
>>
>> After:
>> 0
>>
>arm_spe_0/ts_enable=1,pct_enable=1,pa_enable=1,branch_filter=1,jit
>ter=1,
>> min_latency=0/
>> 0 dummy:u
>> 0 llc-miss
>> 0 tlb-miss
>> 250 branch-miss
>> 0 remote-access
>> 0 l1d-miss
>>
>> WFE Data:
>>
>> 0x4C40 - WFI_WFE_WAIT_CYCLES - Number of cycles waiting at a WFI
>or
>> WFE instruction.
>>
>> - WFE Cycles before the patch for Dual workslot
>> #perf stat -C 20 -e r4C40 sleep 1
>> Performance counter stats for 'CPU(s) 20':
>>
>> 264 r4C40
>> 1.002494168 seconds time elapsed
>>
>> - WFE Cycles for single workslot
>> #perf stat -C 20 -e r4C40 sleep 1
>> Performance counter stats for 'CPU(s) 20':
>>
>> 908,778,351 r4C40
>> 1.002598253 seconds time elapsed
>>
>> drivers/event/octeontx2/otx2_worker_dual.h | 6 +-----
>> 1 file changed, 1 insertion(+), 5 deletions(-)
>>
>> diff --git a/drivers/event/octeontx2/otx2_worker_dual.h
>> b/drivers/event/octeontx2/otx2_worker_dual.h
>> index 5134e3d52..c88420eb4 100644
>> --- a/drivers/event/octeontx2/otx2_worker_dual.h
>> +++ b/drivers/event/octeontx2/otx2_worker_dual.h
>> @@ -29,11 +29,7 @@ otx2_ssogws_dual_get_work(struct
>> otx2_ssogws_state *ws,
>> rte_prefetch_non_temporal(lookup_mem);
>> #ifdef RTE_ARCH_ARM64
>> asm volatile(
>> - " ldr %[tag], [%[tag_loc]] \n"
>> - " ldr %[wqp], [%[wqp_loc]] \n"
>> - " tbz %[tag], 63, done%= \n"
>> - " sevl \n"
>> - "rty%=: wfe \n"
>> + "rty%=: \n"
>> " ldr %[tag], [%[tag_loc]] \n"
>> " ldr %[wqp], [%[wqp_loc]] \n"
>> " tbnz %[tag], 63, rty%= \n"
>> --
>> 2.17.1
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-02-15 13:51 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2020-02-14 6:45 [dpdk-dev] [PATCH] event/octeontx2: remove WFE from dualslot dequeue pbhagavatula
2020-02-15 5:56 ` Gavin Hu
2020-02-15 9:43 ` Pavan Nikhilesh Bhagavatula
2020-02-15 12:23 ` Gavin Hu
2020-02-15 13:51 ` Jerin Jacob
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