On Thu, Mar 13, 2014 at 09:39:02PM -0600, Chris Murphy wrote: > > On Mar 13, 2014, at 8:11 PM, Marc MERLIN <m...@merlins.org> wrote: > > > On Sun, Mar 09, 2014 at 11:33:50AM +0000, Hugo Mills wrote: > >> discard is, except on the very latest hardware, a synchronous command > >> (it's a limitation of the SATA standard), and therefore results in > >> very very poor performance. > > > > Interesting. How do I know if a given SSD will hang on discard? > > Is a Samsung EVO 840 1TB SSD latest hardware enough, or not? :) > > smartctl -a or -x will tell you what SATA revision is in place. The queued > trim support is in SATA Rev 3.1. I'm not certain if this requires only the > drive to support that revision level, or both controller and drive.
I'm not sure I'm seeing this, which field is that? === START OF INFORMATION SECTION === Device Model: Samsung SSD 840 EVO 1TB Serial Number: S1D9NEAD934600N LU WWN Device Id: 5 002538 85009a8ff Firmware Version: EXT0BB0Q User Capacity: 1,000,204,886,016 bytes [1.00 TB] Sector Size: 512 bytes logical/physical Device is: Not in smartctl database [for details use: -P showall] ATA Version is: 8 ATA Standard is: ATA-8-ACS revision 4c Local Time is: Thu Mar 13 22:15:14 2014 PDT SMART support is: Available - device has SMART capability. SMART support is: Enabled === START OF READ SMART DATA SECTION === SMART overall-health self-assessment test result: PASSED General SMART Values: Offline data collection status: (0x00) Offline data collection activity was never started. Auto Offline Data Collection: Disabled. Self-test execution status: ( 0) The previous self-test routine completed without error or no self-test has ever been run. Total time to complete Offline data collection: (15000) seconds. Offline data collection capabilities: (0x53) SMART execute Offline immediate. Auto Offline data collection on/off support. Suspend Offline collection upon new command. No Offline surface scan supported. Self-test supported. No Conveyance Self-test supported. Selective Self-test supported. SMART capabilities: (0x0003) Saves SMART data before entering power-saving mode. Supports SMART auto save timer. Error logging capability: (0x01) Error logging supported. General Purpose Logging supported. Short self-test routine recommended polling time: ( 2) minutes. Extended self-test routine recommended polling time: ( 250) minutes. SCT capabilities: (0x003d) SCT Status supported. SCT Error Recovery Control supported. SCT Feature Control supported. SCT Data Table supported. SMART Attributes Data Structure revision number: 1 Vendor Specific SMART Attributes with Thresholds: ID# ATTRIBUTE_NAME FLAGS VALUE WORST THRESH FAIL RAW_VALUE 5 Reallocated_Sector_Ct PO--CK 100 100 010 - 0 9 Power_On_Hours -O--CK 099 099 000 - 2219 12 Power_Cycle_Count -O--CK 099 099 000 - 659 177 Wear_Leveling_Count PO--C- 099 099 000 - 3 179 Used_Rsvd_Blk_Cnt_Tot PO--C- 100 100 010 - 0 181 Program_Fail_Cnt_Total -O--CK 100 100 010 - 0 182 Erase_Fail_Count_Total -O--CK 100 100 010 - 0 183 Runtime_Bad_Block PO--C- 100 100 010 - 0 187 Reported_Uncorrect -O--CK 100 100 000 - 0 190 Airflow_Temperature_Cel -O--CK 054 041 000 - 46 195 Hardware_ECC_Recovered -O-RC- 200 200 000 - 0 199 UDMA_CRC_Error_Count -OSRCK 100 100 000 - 0 235 Unknown_Attribute -O--C- 099 099 000 - 35 241 Total_LBAs_Written -O--CK 099 099 000 - 12186944165 ||||||_ K auto-keep |||||__ C event count ||||___ R error rate |||____ S speed/performance ||_____ O updated online |______ P prefailure warning -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/ -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html