Resilient Theme Task # 5.5.3 GSRC Annual Symposium · SWAT_poster_draft_3.pptx Author: Pradeep...
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GSRC Annual Symposium September 28, 2010 through October 1, 2010 Detection Results Low SDC rate for all apps <0.5% of injections SDCs Short detection latency >90% in <100K instr ⇒Low-cost symptom detection feasible for HW faults Diagnosis Results >95% successful diagnosis Latency <10M ⇒invisible µarch-level diagnosis for repair ⇒SWAT diagnoses faults in single and multi-core systems Recovery Results Pradeep Ramachandran, Siva Kumar SastryHari, Manlap Li, SwarupSahoo, Robert Smolinsk, Xin Fu, Lei Chen, SaritaAdve, VikramAdve Resilient Theme Task # 5.5.3 The Reliability Threat Technology scaling ⇒ smaller devices vulnerable to failures Increased in-the-field failures in commodity systems Need low-cost detection, diagnosis, recovery, repair solutions Traditional solutions ⇒ high area, performance, power SWAT: A Comprehensive Low Cost Solution Fault Detection [ASPLOS ʻ08, DSN ʻ08] Fault Recovery [submitted] Key Findings SWAT effective for permanent, transient faults in many apps Detection: <0.5% SDC rate in SPEC, server, media apps Low overheads during fault-free execution Recovery: Majority of faults recoverable in <100K instructions <5% perf, near-zero area impact from recovery operations Diagnosis: >95% of detected faults successfully diagnosed Faulty core identified without spare core TMR/DMR only for diagnosis ⇒ does not impact fault-free exec Fault Diagnosis [DSN ʼ08, MICRO ʻ09] Transient errors Wear-out Design Bugs … and so on Goal: Effective, quick detection with minimal fault-free impact Use symptom detectors to monitor anomalous SW execution Simple hardware detectors with low area overheads Low-cost SW detectors to aid HW detectors Goal: Low-cost fault recovery in the presence of I/O HW checkpoint to restore system state Low-cost recovery for proc + memory Buffer external outputs in dedicated HW First low-cost implementation w/ simple HW Avoids commonly ignored output-commit problem Leverage SW support for device reset, input replay Goal: Diagnose fault source without affecting fault-free exec ⇒ No spares for diagnosis Diagnose faulty core even when symptom from fault-free core Fatal Traps Div by zero, RED state, etc. Hangs Simple HW hang detector Kernel Panic OS panics due to fault High OS High contiguous OS activity App Abort App abort due to fault 0% 20% 40% 60% 80% 100% Full No-Device No-I/O Full No-Device No-I/O Full No-Device No-I/O Full No-Device No-I/O 100K 10M 100K 10M Permanents Transients Injected Faults Potential SDC DUE Recovered Masked 6.3% 2.5% 2.3% 1.5% Ongoing and Future Work Ongoing: Prototyping SWAT on FPGA Implement SWAT firmware in OpenSolaris Demonstrate SWAT on multicore OpenSPARC FPGA Leverage Univ. of Michigan CrashTest for fault injection Understand when/why SWAT works Evaluate SWAT for off-core faults, other fault models A B C D Challenges Multithreaded applications Full-system deterministic replay No known good core Isolated deterministic replay Emulated TMR Key Ideas T A T B T C T D T A T A T B T C T D T A T B T C T D T A T B T C T D 0% 20% 40% 60% 80% 100% Decoder INT ALU Reg Dbus Int reg ROB RAT AGEN Average Detected Faults CorrectlyDiagnosed Undiagnosed 99 100 99 87 100 78 99 95.9 1 10 100 10K 100K 1M 2M 5M 10M Client exec time with buffer/ without buffer Chkpt Interval (in instructions) apache sshd squid mysql Fault Out-of-Bounds HW/SW co-designed detector Monitor legal limit of addresses Low perf, area overhead iSWAT Compiler support to detect faults Use likely invariants as detectors Low false +ves, perf. impact 0% 20% 40% 60% 80% 100% SPEC Server Media SPEC Server Media Permanents Transients Total injections Masked Detected App-Tolerated SDC 0.1 0.1 0.2 0.2 0.3 0.5 * Does not include iSWAT detectors Low overheads @ 100K inst <5% perf, <2KB area Practical sol ⇒delay <1M inst High recovery at 100K interval Low perf, area impact ⇒ SWAT effective for low-cost fault recovery
Transcript of Resilient Theme Task # 5.5.3 GSRC Annual Symposium · SWAT_poster_draft_3.pptx Author: Pradeep...
GSRC Annual Symposium
September 28, 2010 through
October 1, 2010
Detection Results
Low SDC rate for all apps
<0.5% of injections SDCs
Short detection latency
>90% in <100K instr
⇒ Low-cost symptom detection feasible for HW faults
Diagnosis Results >95% successful diagnosis
Latency <10M ⇒invisible
µarch-level diagnosis for repair
⇒ SWAT diagnoses faults in single and multi-core systems
Recovery Results
Pradeep Ramachandran, Siva Kumar SastryHari, Manlap Li, SwarupSahoo, Robert Smolinsk, Xin Fu, Lei Chen, SaritaAdve, VikramAdve
Resilient Theme Task # 5.5.3
The Reliability Threat
Technology scaling ⇒ smaller devices vulnerable to failures
Increased in-the-field failures in commodity systems
Need low-cost detection, diagnosis, recovery, repair solutions
Traditional solutions ⇒ high area, performance, power
SWAT: A Comprehensive Low Cost Solution
Fault Detection [ASPLOS ʻ08, DSN ʻ08] Fault Recovery [submitted]
Key Findings SWAT effective for permanent, transient faults in many apps
Detection: <0.5% SDC rate in SPEC, server, media apps
Low overheads during fault-free execution
Recovery: Majority of faults recoverable in <100K instructions
<5% perf, near-zero area impact from recovery operations
Diagnosis: >95% of detected faults successfully diagnosed
Faulty core identified without spare core
TMR/DMR only for diagnosis ⇒ does not impact fault-free exec
Fault Diagnosis [DSN ʼ08, MICRO ʻ09]
Transient errors Wear-out Design Bugs … and so on
Goal: Effective, quick detection with minimal fault-free impact
Use symptom detectors to monitor anomalous SW execution
Simple hardware detectors with low area overheads
Low-cost SW detectors to aid HW detectors
Goal: Low-cost fault recovery in the presence of I/O
HW checkpoint to restore system state
Low-cost recovery for proc + memory
Buffer external outputs in dedicated HW
First low-cost implementation w/ simple HW
Avoids commonly ignored output-commit problem
Leverage SW support for device reset, input replay
Goal: Diagnose fault source without affecting fault-free exec
⇒ No spares for diagnosis
Diagnose faulty core even when symptom from fault-free core
Fatal Traps
Div by zero, RED state, etc.
Hangs
Simple HW hang detector
Kernel Panic
OS panics due to fault
High OS
High contiguous OS activity
App Abort
App abort due to fault
0% 20% 40% 60% 80%
100%
Full
No-
Dev
ice
No-
I/O
Full
No-
Dev
ice
No-
I/O
Full
No-
Dev
ice
No-
I/O
Full
No-
Dev
ice
No-
I/O
100K 10M 100K 10M
Permanents Transients
Inje
cted
Fau
lts
Potential SDC DUE Recovered Masked
6.3% 2.5% 2.3% 1.5%
Ongoing and Future Work Ongoing: Prototyping SWAT on FPGA
Implement SWAT firmware in OpenSolaris
Demonstrate SWAT on multicore OpenSPARC FPGA
Leverage Univ. of Michigan CrashTest for fault injection
Understand when/why SWAT works
Evaluate SWAT for off-core faults, other fault models
A B C D Challenges
Multithreaded applications
Full-system deterministic
replay
No known good core
Isolated deterministic
replay
Emulated TMR
Key Ideas TA TB TC TD
TA
TA TB TC TD
TA TB TC TD
TA TB TC TD
0%
20%
40%
60%
80%
100%
Dec
oder
INT
ALU
Reg
Dbu
s
Int r
eg
RO
B
RAT
AG
EN
Aver
age
Det
ecte
d Fa
ults
CorrectlyDiagnosed Undiagnosed
99 100 99 87 100 78 99 95.9
1
10
100
10K 100K 1M 2M 5M 10M Clie
nt e
xec
time
with
buf
fer/
with
out b
uffe
r
Chkpt Interval (in instructions)
apache
sshd
squid
mysql
Fault
Out-of-Bounds HW/SW co-designed detector
Monitor legal limit of addresses Low perf, area overhead
iSWAT Compiler support to detect faults Use likely invariants as detectors
Low false +ves, perf. impact
0%
20%
40%
60%
80%
100%
SP
EC
Ser
ver
Med
ia
SP
EC
Ser
ver
Med
ia
Permanents Transients
Tota
l inj
ectio
ns
Masked Detected App-Tolerated SDC
0.1 0.1 0.2 0.2 0.3 0.5
* Does not include iSWAT detectors
Low overheads @ 100K inst
<5% perf, <2KB area
Practical sol ⇒delay <1M inst
High recovery at 100K interval
Low perf, area impact
⇒ SWAT effective for low-cost fault recovery
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