Hi, Steve Right, Please see below portion log from ftrace and blktrace, There is no any impact on blktrace. > >Looking at the code from >git://git.kernel.org/pub/scm/linux/kernel/git/axboe/blktrace.git > >It appears that it does not rely on the ftrace ring buffers. > >So I'm guessing blktrace is not affected by this patch. > >-- Steve #/blktrace -d /dev/block/sdd14 -o - | ./blkparse -i - 8,62 3 1162 0.213039583 4116 P N [iozone] 8,62 3 1163 0.213041146 4116 U N [iozone] 1 8,62 3 1164 0.213042708 4116 I WS 39573632 + 128 [iozone] 8,62 3 1165 0.213044791 4116 D WS 39573632 + 128 [iozone] 8,48 3 1166 0.213585416 4116 A WS 39573760 + 128 <- (8,62) 342272 8,62 3 1167 0.213590104 4116 Q WS 39573760 + 128 [iozone] 8,62 3 1168 0.213592187 4116 G WS 39573760 + 128 [iozone] 8,62 3 1169 0.213594271 4116 P N [iozone] 8,62 3 1170 0.213595833 4116 U N [iozone] 1 8,62 3 1171 0.213597396 4116 I WS 39573760 + 128 [iozone] 8,62 3 1172 0.213600000 4116 D WS 39573760 + 128 [iozone] 8,48 3 1173 0.214092187 4116 A WS 39573888 + 128 <- (8,62) 342400 8,62 3 1174 0.214094791 4116 Q WS 39573888 + 128 [iozone] 8,62 3 1175 0.214097916 4116 G WS 39573888 + 128 [iozone] 8,62 3 1176 0.214102604 4116 P N [iozone] 8,62 3 1177 0.214105208 4116 U N [iozone] 1 8,62 3 1178 0.214106771 4116 I WS 39573888 + 128 [iozone] 8,62 3 1179 0.214111458 4116 D WS 39573888 + 128 [iozone] 8,48 3 1180 0.216531771 4115 A WS 39546496 + 128 <- (8,62) 315008 8,62 3 1181 0.216534896 4115 Q WS 39546496 + 128 [iozone] 8,62 3 1182 0.216538021 4115 G WS 39546496 + 128 [iozone] 8,62 3 1183 0.216540625 4115 P N [iozone] 8,62 3 1184 0.216543229 4115 U N [iozone] 1 8,62 3 1185 0.216544791 4115 I WS 39546496 + 128 [iozone] 8,62 3 1186 0.216547396 4115 D WS 39546496 + 128 [iozone] 8,48 3 1187 0.217146354 4115 A WS 39546624 + 128 <- (8,62) 315136 8,62 3 1188 0.217148437 4115 Q WS 39546624 + 128 [iozone] 8,62 3 1189 0.217151041 4115 G WS 39546624 + 128 [iozone] 8,62 3 1190 0.217153646 4115 P N [iozone] 8,62 3 1191 0.217155208 4115 U N [iozone] 1 8,62 3 1192 0.217156771 4115 I WS 39546624 + 128 [iozone] 8,62 3 1193 0.217159896 4115 D WS 39546624 + 128 [iozone] 8,48 3 1194 0.217712500 4115 A WS 39546752 + 128 <- (8,62) 315264 8,62 3 1195 0.217714583 4115 Q WS 39546752 + 128 [iozone] 8,62 3 1196 0.217717708 4115 G WS 39546752 + 128 [iozone] 8,62 3 1197 0.217722396 4115 P N [iozone] 8,62 3 1198 0.217724479 4115 U N [iozone] 1 8,62 3 1199 0.217726041 4115 I WS 39546752 + 128 [iozone] 8,62 3 1200 0.217728646 4115 D WS 39546752 + 128 [iozone] 8,62 5 1150 0.198047916 0 C WS 39569920 + 128 [0] 8,62 4 1104 0.198104687 0 C WS 39576448 + 128 [0] 8,48 5 1151 0.198182291 4116 A WS 39570048 + 128 <- (8,62) 338560 8,62 5 1152 0.198183333 4116 Q WS 39570048 + 128 [iozone] 8,62 5 1153 0.198184375 4116 G WS 39570048 + 128 [iozone] 8,62 5 1154 0.198185937 4116 P N [iozone] 8,62 5 1155 0.198186458 4116 U N [iozone] 1 8,62 5 1156 0.198186979 4116 I WS 39570048 + 128 [iozone] 8,62 5 1157 0.198188541 4116 D WS 39570048 + 128 [iozone] 8,48 4 1105 0.198218229 4114 A WS 39576576 + 128 <- (8,62) 345088 8,62 4 1106 0.198219271 4114 Q WS 39576576 + 128 [iozone] 8,62 4 1107 0.198220312 4114 G WS 39576576 + 128 [iozone] 8,62 4 1108 0.198221354 4114 P N [iozone] 8,62 4 1109 0.198221875 4114 U N [iozone] 1 8,62 4 1110 0.198222396 4114 I WS 39576576 + 128 [iozone] 8,62 4 1111 0.198223437 4114 D WS 39576576 + 128 [iozone] 8,62 4 1112 0.198245312 4114 C WS 39594368 + 128 [0] 8,62 5 1158 0.198336979 0 C WS 39570048 + 128 [0] 8,62 4 1113 0.198409375 0 C WS 39576576 + 128 [0] 8,48 5 1159 0.199219791 4113 A WS 39594624 + 128 <- (8,62) 363136 8,62 5 1160 0.199220833 4113 Q WS 39594624 + 128 [iozone] 8,62 5 1161 0.199222396 4113 G WS 39594624 + 128 [iozone] 8,62 5 1162 0.199223437 4113 P N [iozone] 8,62 5 1163 0.199224479 4113 U N [iozone] 1 8,62 5 1164 0.199225000 4113 I WS 39594624 + 128 [iozone] 8,62 5 1165 0.199226562 4113 D WS 39594624 + 128 [iozone] 8,48 4 1114 0.199235937 4116 A WS 39570176 + 128 <- (8,62) 338688 8,62 4 1115 0.199236979 4116 Q WS 39570176 + 128 [iozone] 8,62 4 1116 0.199238021 4116 G WS 39570176 + 128 [iozone] 8,62 4 1117 0.199239062 4116 P N [iozone] 8,62 4 1118 0.199239583 4116 U N [iozone] 1 8,62 4 1119 0.199240104 4116 I WS 39570176 + 128 [iozone] 8,62 4 1120 0.199241666 4116 D WS 39570176 + 128 [iozone] 8,62 4 1121 0.199404687 0 C WS 39570176 + 128 [0] 8,62 5 1166 0.199467187 0 C WS 39594624 + 128 [0] 8,48 5 1167 0.199960416 4113 A WS 39594752 + 128 <- (8,62) 363264 8,62 5 1168 0.199960937 4113 Q WS 39594752 + 128 [iozone] 8,62 5 1169 0.199961979 4113 G WS 39594752 + 128 [iozone] 8,62 5 1170 0.199963541 4113 P N [iozone] 8,62 5 1171 0.199964062 4113 U N [iozone] 1 8,62 5 1172 0.199964583 4113 I WS 39594752 + 128 [iozone] 8,62 5 1173 0.199966146 4113 D WS 39594752 + 128 [iozone] 8,48 4 1122 0.199970833 4116 A WS 39570304 + 128 <- (8,62) 338816 8,62 4 1123 0.199971875 4116 Q WS 39570304 + 128 [iozone] 8,62 4 1124 0.199972916 4116 G WS 39570304 + 128 [iozone] 8,62 4 1125 0.199973958 4116 P N [iozone] 8,62 4 1126 0.199974479 4116 U N [iozone] 1 #Cat trace iozone-4055 [000] .... 665.039276: block_unplug: [iozone] 1 Sync iozone-4055 [000] ...1 665.039278: block_rq_insert: 8,48 WS 0 () 39604352 + 128 tag=18 [iozone] iozone-4055 [000] ...1 665.039280: block_rq_issue: 8,48 WS 0 () 39604352 + 128 tag=18 [iozone] iozone-4055 [000] ...1 665.039284: scsi_dispatch_cmd_start: host_no=0 channel=0 id=0 lun=3 data_sgl=16 prot_sgl=0 prot_op=SCSI_PROT_NORMAL tag=18 cmnd=(WRITE_10 lba=4950544 txlen=16 protect=0 raw=2a 00 00 4b 8a 10 00 00 10 00) iozone-4056 [002] .... 665.039284: block_dirty_buffer: 8,62 sector=44375 size=4096 <idle>-0 [000] d.h2 665.039319: scsi_dispatch_cmd_done: host_no=0 channel=0 id=0 lun=3 data_sgl=16 prot_sgl=0 prot_op=SCSI_PROT_NORMAL tag=24 cmnd=(WRITE_10 lba=4944016 txlen=16 protect=0 raw=2a 00 00 4b 70 90 00 00 10 00) result=(driver=DRIVER_OK host=DID_OK message=COMMAND_COMPLETE status=SAM_STAT_GOOD) <idle>-0 [000] d.h3 665.039321: block_rq_complete: 8,48 WS () 39552128 + 128 tag=24 [0] iozone-4056 [002] .... 665.039325: block_dirty_buffer: 8,62 sector=44380 size=4096 iozone-4058 [003] .... 665.039362: block_bio_remap: 8,48 WS 39568768 + 128 <- (8,62) 337280 iozone-4058 [003] .... 665.039364: block_bio_queue: 8,48 WS 39568768 + 128 [iozone] iozone-4058 [003] ...1 665.039366: block_getrq: 8,48 WS 39568768 + 128 [iozone] iozone-4058 [003] ...1 665.039368: block_plug: [iozone] iozone-4058 [003] .... 665.039369: block_unplug: [iozone] 1 Sync iozone-4058 [003] ...1 665.039371: block_rq_insert: 8,48 WS 0 () 39568768 + 128 tag=16 [iozone] iozone-4058 [003] ...1 665.039373: block_rq_issue: 8,48 WS 0 () 39568768 + 128 tag=16 [iozone] iozone-4058 [003] ...1 665.039375: scsi_dispatch_cmd_start: host_no=0 channel=0 id=0 lun=3 data_sgl=16 prot_sgl=0 prot_op=SCSI_PROT_NORMAL tag=16 cmnd=(WRITE_10 lba=4946096 txlen=16 protect=0 raw=2a 00 00 4b 78 b0 00 00 10 00) iozone-4057 [001] .... 665.039402: block_touch_buffer: 8,62 sector=1034 size=4096 <idle>-0 [000] d.h2 665.039410: scsi_dispatch_cmd_done: host_no=0 channel=0 id=0 lun=3 data_sgl=16 prot_sgl=0 prot_op=SCSI_PROT_NORMAL tag=18 cmnd=(WRITE_10 lba=4950544 txlen=16 protect=0 raw=2a 00 00 4b 8a 10 00 00 10 00) result=(driver=DRIVER_OK host=DID_OK message=COMMAND_COMPLETE status=SAM_STAT_GOOD) <idle>-0 [000] d.h3 665.039412: block_rq_complete: 8,48 WS () 39604352 + 128 tag=18 [0] iozone-4057 [001] .... 665.039415: block_dirty_buffer: 8,62 sector=40096 size=4096 iozone-4056 [002] .... 665.039425: block_bio_remap: 8,48 WS 39586432 + 128 <- (8,62) 354944 iozone-4056 [002] .... 665.039427: block_bio_queue: 8,48 WS 39586432 + 128 [iozone] iozone-4057 [001] .... 665.039427: block_dirty_buffer: 8,62 sector=40097 size=4096 iozone-4056 [002] ...1 665.039430: block_getrq: 8,48 WS 39586432 + 128 [iozone] iozone-4056 [002] ...1 665.039432: block_plug: [iozone] iozone-4056 [002] .... 665.039434: block_unplug: [iozone] 1 Sync iozone-4056 [002] ...1 665.039435: block_rq_insert: 8,48 WS 0 () 39586432 + 128 tag=30 [iozone] iozone-4057 [001] .... 665.039437: block_dirty_buffer: 8,62 sector=40098 size=4096 iozone-4056 [002] ...1 665.039437: block_rq_issue: 8,48 WS 0 () 39586432 + 128 tag=30 [iozone] iozone-4056 [002] ...1 665.039439: scsi_dispatch_cmd_start: host_no=0 channel=0 id=0 lun=3 data_sgl=16 prot_sgl=0 prot_op=SCSI_PROT_NORMAL tag=30 cmnd=(WRITE_10 lba=4948304 txlen=16 protect=0 raw=2a 00 00 4b 81 50 00 00 10 00) Especially, the ftrace log with tag information, I can easily figure out one I/O request between block layer and SCSI. //Bean Huo
