xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

powerpc/8xx: Only perform perf counting when perf is in use.

Browse Source 
In TLB miss handlers, updating the perf counter is only useful
when performing a perf analysis. As it has a noticeable overhead,
let's only do it when needed.

In order to do so, the exit of the miss handlers will be patched
when starting/stopping 'perf': the first register restore
instruction of each exit point will be replaced by a jump to
the counting code.

Once this is done, CONFIG_PPC_8xx_PERF_EVENT becomes useless as
this feature doesn't add any overhead.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Christophe Leroy
2018-01-12 13:45:23 +01:00
committed by Michael Ellerman
parent bb9b5a8332
commit cd99ddbea2
6 changed files with 88 additions and 32 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
arch/powerpc/include/asm/ppc-opcode.h
View File

@@ -236,6 +236,7 @@
#define PPC_INST_RFCI 0x4c000066
#define PPC_INST_RFDI 0x4c00004e
#define PPC_INST_RFMCI 0x4c00004c
#define PPC_INST_MFSPR 0x7c0002a6
#define PPC_INST_MFSPR_DSCR 0x7c1102a6
#define PPC_INST_MFSPR_DSCR_MASK 0xfc1ffffe
#define PPC_INST_MTSPR_DSCR 0x7c1103a6
@@ -383,6 +384,7 @@
#define __PPC_ME64(s) __PPC_MB64(s)
#define __PPC_BI(s) (((s) & 0x1f) << 16)
#define __PPC_CT(t) (((t) & 0x0f) << 21)
#define __PPC_SPR(r) ((((r) & 0x1f) << 16) | ((((r) >> 5) & 0x1f) << 11))
/*
* Only use the larx hint bit on 64bit CPUs. e500v1/v2 based CPUs will treat a