From fd8be18f3f33c41f89f8cceafb9f23e9562cebcf Mon Sep 17 00:00:00 2001 From: "Kenneth D. Merry" Date: Fri, 27 Feb 2015 21:35:36 +0000 Subject: [PATCH] Fix I/O size calculation for pass(4) driver requests and add latency tracking. It is important to subtract the residual from the requested transfer size to see how much data was actually transferred. With tape drives in particular, it is common to request more data than is returned. Also, add I/O latency tracking for CAM requests issued by cam_periph_runccb(). If the caller supplies a struct devstat, and the I/O is a SCSI or ATA I/O, we will track the elapsed time to provide I/O latency statistics for the request. sys/cam/scsi/cam_periph.c: In cam_periph_runccb(), subtract the residual when reporting I/O totals to devstat(9) for SCSI and ATA passthrough requests. In cam_periph_runccb(), grab the I/O start time and supply the start time to devstat_end_transaction() so that it can calculate the elapsed I/O time. Sponsored by: Spectra Logic MFC after: 1 week --- sys/cam/cam_periph.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/sys/cam/cam_periph.c b/sys/cam/cam_periph.c index 87c1bdd9881..2544d2756c7 100644 --- a/sys/cam/cam_periph.c +++ b/sys/cam/cam_periph.c @@ -1048,8 +1048,11 @@ cam_periph_runccb(union ccb *ccb, cam_flags camflags, u_int32_t sense_flags, struct devstat *ds) { + struct bintime *starttime; + struct bintime ltime; int error; + starttime = NULL; xpt_path_assert(ccb->ccb_h.path, MA_OWNED); /* @@ -1057,8 +1060,11 @@ cam_periph_runccb(union ccb *ccb, * this particular type of ccb, record the transaction start. */ if ((ds != NULL) && (ccb->ccb_h.func_code == XPT_SCSI_IO || - ccb->ccb_h.func_code == XPT_ATA_IO)) - devstat_start_transaction(ds, NULL); + ccb->ccb_h.func_code == XPT_ATA_IO)) { + starttime = <ime; + binuptime(starttime); + devstat_start_transaction(ds, starttime); + } ccb->ccb_h.cbfcnp = cam_periph_done; xpt_action(ccb); @@ -1086,22 +1092,22 @@ cam_periph_runccb(union ccb *ccb, if (ds != NULL) { if (ccb->ccb_h.func_code == XPT_SCSI_IO) { devstat_end_transaction(ds, - ccb->csio.dxfer_len, + ccb->csio.dxfer_len - ccb->csio.resid, ccb->csio.tag_action & 0x3, ((ccb->ccb_h.flags & CAM_DIR_MASK) == CAM_DIR_NONE) ? DEVSTAT_NO_DATA : (ccb->ccb_h.flags & CAM_DIR_OUT) ? DEVSTAT_WRITE : - DEVSTAT_READ, NULL, NULL); + DEVSTAT_READ, NULL, starttime); } else if (ccb->ccb_h.func_code == XPT_ATA_IO) { devstat_end_transaction(ds, - ccb->ataio.dxfer_len, + ccb->ataio.dxfer_len - ccb->ataio.resid, ccb->ataio.tag_action & 0x3, ((ccb->ccb_h.flags & CAM_DIR_MASK) == CAM_DIR_NONE) ? DEVSTAT_NO_DATA : (ccb->ccb_h.flags & CAM_DIR_OUT) ? DEVSTAT_WRITE : - DEVSTAT_READ, NULL, NULL); + DEVSTAT_READ, NULL, starttime); } }