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| author | svemuri <none@none> | 2008-05-09 13:07:43 -0700 |
|---|---|---|
| committer | svemuri <none@none> | 2008-05-09 13:07:43 -0700 |
| commit | bd6b3d1f3fc963bf15d7069a0576d0fa2a0802aa (patch) | |
| tree | 77011141fa7f22588eef0f819bcdcf71fb2245aa /usr/src/uts/sfmmu | |
| parent | fb81f5532aeec22da92ae11861736f38ef47528a (diff) | |
| download | illumos-joyent-bd6b3d1f3fc963bf15d7069a0576d0fa2a0802aa.tar.gz | |
6690827 too many simultaneous SIGSEGVs cause Batoka to fall over
Diffstat (limited to 'usr/src/uts/sfmmu')
| -rw-r--r-- | usr/src/uts/sfmmu/ml/sfmmu_asm.s | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/usr/src/uts/sfmmu/ml/sfmmu_asm.s b/usr/src/uts/sfmmu/ml/sfmmu_asm.s index a80c34b200..1bd42ae52c 100644 --- a/usr/src/uts/sfmmu/ml/sfmmu_asm.s +++ b/usr/src/uts/sfmmu/ml/sfmmu_asm.s @@ -1590,12 +1590,24 @@ sfmmu_hblk_hash_rm(struct hmehash_bucket *hmebp, struct hme_blk *hmeblkp, #error - the size of hmehash_bucket structure is not power of 2 #endif +/* + * Enable backoff to significantly reduce locking overhead and reduce a chance + * of xcall timeout. This is only enabled for sun4v as a Makefile compile- + * time option. + * The rd %ccr is better for performance compared to a non pipeline releasing + * tight spin on N2/VF. + * Backoff based fix is a temporary solution and doesn't allow scaling above + * lock saturation point. The final fix is to eliminate HMELOCK_ENTER() + * to avoid xcall timeouts and improve GET_TTE() performance. + */ + #ifdef HMELOCK_BACKOFF_ENABLE #define HMELOCK_BACKOFF(reg, val) \ set val, reg ;\ - brnz reg, . ;\ - dec reg + rd %ccr, %g0 ;\ + brnz reg, .-4 ;\ + dec reg #define CAS_HME(tmp1, tmp2, exitlabel, asi) \ mov 0xff, tmp2 ;\ @@ -1609,13 +1621,21 @@ sfmmu_hblk_hash_rm(struct hmehash_bucket *hmebp, struct hme_blk *hmeblkp, casa [tmp1]asi, %g0, tmp2 ;\ brz,a,pt tmp2, label/**/2 ;\ membar #LoadLoad ;\ + HMELOCK_BACKOFF(tmp2,0x8) ;\ + CAS_HME(tmp1, tmp2, label/**/2, asi) ;\ + HMELOCK_BACKOFF(tmp2,0x10) ;\ + CAS_HME(tmp1, tmp2, label/**/2, asi) ;\ + HMELOCK_BACKOFF(tmp2,0x20) ;\ + CAS_HME(tmp1, tmp2, label/**/2, asi) ;\ + HMELOCK_BACKOFF(tmp2,0x40) ;\ + CAS_HME(tmp1, tmp2, label/**/2, asi) ;\ HMELOCK_BACKOFF(tmp2,0x80) ;\ CAS_HME(tmp1, tmp2, label/**/2, asi) ;\ +label/**/1: ;\ HMELOCK_BACKOFF(tmp2,0x100) ;\ CAS_HME(tmp1, tmp2, label/**/2, asi) ;\ HMELOCK_BACKOFF(tmp2,0x200) ;\ CAS_HME(tmp1, tmp2, label/**/2, asi) ;\ -label/**/1: ;\ HMELOCK_BACKOFF(tmp2,0x400) ;\ CAS_HME(tmp1, tmp2, label/**/2, asi) ;\ HMELOCK_BACKOFF(tmp2,0x800) ;\ |