From: Pavan Nikhilesh <pbhagavat...@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 <pbhagavat...@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
