From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>,
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Subject: [PATCH 2/2] powerpc/64s: idle skip POWER9 DD1 and DD2.0 specific workarounds on DD2.1
Date: Fri, 20 Oct 2017 14:54:44 +1000 [thread overview]
Message-ID: <20171020045444.4539-3-npiggin@gmail.com> (raw)
In-Reply-To: <20171020045444.4539-1-npiggin@gmail.com>
DD2.1 does not have to flush the ERAT after a state-loss idle. It also
does not have to save and restore MMCR0.
Performance testing was done on a DD2.1 using only the stop0 idle state
(the shallowest state which supports state loss), using context_switch
selftest configured to ping-poing between two threads on the same core
and two different cores.
Performance improvement for same core is 7.0%, different cores is 14.8%.
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kernel/idle_book3s.S | 39 ++++++++++++++++++++++++++++-----------
1 file changed, 28 insertions(+), 11 deletions(-)
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S
index 1125c9be9e06..3531a3e727d2 100644
--- a/arch/powerpc/kernel/idle_book3s.S
+++ b/arch/powerpc/kernel/idle_book3s.S
@@ -112,12 +112,14 @@ power9_save_additional_sprs:
std r4, STOP_HFSCR(r13)
mfspr r3, SPRN_MMCRA
- mfspr r4, SPRN_MMCR1
+ mfspr r4, SPRN_MMCR0
std r3, STOP_MMCRA(r13)
- std r4, STOP_MMCR1(r13)
+ std r4, _MMCR0(r1)
- mfspr r3, SPRN_MMCR2
- std r3, STOP_MMCR2(r13)
+ mfspr r3, SPRN_MMCR1
+ mfspr r4, SPRN_MMCR2
+ std r3, STOP_MMCR1(r13)
+ std r4, STOP_MMCR2(r13)
blr
power9_restore_additional_sprs:
@@ -135,11 +137,14 @@ power9_restore_additional_sprs:
ld r4, STOP_MMCRA(r13)
mtspr SPRN_HFSCR, r3
mtspr SPRN_MMCRA, r4
- /* We have already restored PACA_MMCR0 */
- ld r3, STOP_MMCR1(r13)
- ld r4, STOP_MMCR2(r13)
- mtspr SPRN_MMCR1, r3
- mtspr SPRN_MMCR2, r4
+
+ ld r3, _MMCR0(r1)
+ ld r4, STOP_MMCR1(r13)
+ mtspr SPRN_MMCR0, r3
+ mtspr SPRN_MMCR1, r4
+
+ ld r3, STOP_MMCR2(r13)
+ mtspr SPRN_MMCR2, r3
blr
/*
@@ -357,6 +362,7 @@ power_enter_stop:
b pnv_wakeup_noloss
.Lhandle_esl_ec_set:
+BEGIN_FTR_SECTION
/*
* POWER9 DD2 can incorrectly set PMAO when waking up after a
* state-loss idle. Saving and restoring MMCR0 over idle is a
@@ -364,6 +370,10 @@ power_enter_stop:
*/
mfspr r4,SPRN_MMCR0
std r4,_MMCR0(r1)
+FTR_SECTION_ELSE
+ nop
+ nop
+ALT_FTR_SECTION_END_IFCLR(CPU_FTR_POWER9_DD1 | CPU_FTR_POWER9_DD20)
/*
* Check if the requested state is a deep idle state.
@@ -555,15 +565,22 @@ pnv_restore_hyp_resource_arch300:
* then clear bit 60 in MMCRA to ensure the PMU starts running.
*/
blt cr3,1f
+BEGIN_FTR_SECTION
+ nop
+ nop
+ nop
+ nop
+FTR_SECTION_ELSE
PPC_INVALIDATE_ERAT
ld r1,PACAR1(r13)
+ ld r4,_MMCR0(r1)
+ mtspr SPRN_MMCR0,r4
+ALT_FTR_SECTION_END_IFCLR(CPU_FTR_POWER9_DD1 | CPU_FTR_POWER9_DD20)
mfspr r4,SPRN_MMCRA
ori r4,r4,(1 << (63-60))
mtspr SPRN_MMCRA,r4
xori r4,r4,(1 << (63-60))
mtspr SPRN_MMCRA,r4
- ld r4,_MMCR0(r1)
- mtspr SPRN_MMCR0,r4
1:
/*
* POWER ISA 3. Use PSSCR to determine if we
--
2.13.3
next prev parent reply other threads:[~2017-10-20 4:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-20 4:54 [PATCH 0/2] Add POWER9 DD2.0 feature, remove idle workarounds in DD2.1 Nicholas Piggin
2017-10-20 4:54 ` [PATCH 1/2] powerpc: add POWER9_DD20 feature Nicholas Piggin
2017-10-20 4:54 ` Nicholas Piggin [this message]
2017-10-20 11:11 ` [PATCH 2/2] powerpc/64s: idle skip POWER9 DD1 and DD2.0 specific workarounds on DD2.1 Vaidyanathan Srinivasan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20171020045444.4539-3-npiggin@gmail.com \
--to=npiggin@gmail.com \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=svaidy@linux.vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.