From b0dc148eab1a65131f9fe9ade2abf6107e934008 Mon Sep 17 00:00:00 2001 From: Douglas Gilbert Date: Mon, 25 Jan 2021 15:26:51 -0500 Subject: [PATCH] fio: add hipri option to sg engine Adds hipri option to the Linux sg driver engine. This turns on the SGV4_FLAG_HIPRI flag in recent sg drivers (January 2021) on READ and WRITE commands (and not on UNMAP (trim), VERIFY, etc). Uses blk_poll() and the mq_poll() callback in SCSI LLDs. The mechanism is also called "iopoll". The Linux sg engine in fio uses the struct sg_io_hdr based interface known as the sg driver "v3" interface. Linux sg drivers in the kernel prior to January 2021 (sg version 4.0.12) will just ignore the SGV4_FLAG_HIPRI flag and do normal completions where LLDs indicate command completion with a (software) interrupt or similar mechanism. Update fio.1 (manpage) with new hipri sg engine option. Signed-off-by: Douglas Gilbert Signed-off-by: Jens Axboe --- engines/sg.c | 22 +++++++++++++++++++++- fio.1 | 10 ++++++++++ 2 files changed, 31 insertions(+), 1 deletion(-) diff --git a/engines/sg.c b/engines/sg.c index a1a6de4c..0c2d2c8b 100644 --- a/engines/sg.c +++ b/engines/sg.c @@ -60,6 +60,10 @@ #ifdef FIO_HAVE_SGIO +#ifndef SGV4_FLAG_HIPRI +#define SGV4_FLAG_HIPRI 0x800 +#endif + enum { FIO_SG_WRITE = 1, FIO_SG_WRITE_VERIFY = 2, @@ -68,12 +72,22 @@ enum { struct sg_options { void *pad; + unsigned int hipri; unsigned int readfua; unsigned int writefua; unsigned int write_mode; }; static struct fio_option options[] = { + { + .name = "hipri", + .lname = "High Priority", + .type = FIO_OPT_STR_SET, + .off1 = offsetof(struct sg_options, hipri), + .help = "Use polled IO completions", + .category = FIO_OPT_C_ENGINE, + .group = FIO_OPT_G_SG, + }, { .name = "readfua", .lname = "sg engine read fua flag support", @@ -527,6 +541,8 @@ static int fio_sgio_prep(struct thread_data *td, struct io_u *io_u) else hdr->cmdp[0] = 0x88; // read(16) + if (o->hipri) + hdr->flags |= SGV4_FLAG_HIPRI; if (o->readfua) hdr->cmdp[1] |= 0x08; @@ -542,6 +558,8 @@ static int fio_sgio_prep(struct thread_data *td, struct io_u *io_u) hdr->cmdp[0] = 0x2a; // write(10) else hdr->cmdp[0] = 0x8a; // write(16) + if (o->hipri) + hdr->flags |= SGV4_FLAG_HIPRI; if (o->writefua) hdr->cmdp[1] |= 0x08; break; @@ -865,6 +883,7 @@ static int fio_sgio_init(struct thread_data *td) { struct sgio_data *sd; struct sgio_trim *st; + struct sg_io_hdr *h3p; int i; sd = calloc(1, sizeof(*sd)); @@ -880,12 +899,13 @@ static int fio_sgio_init(struct thread_data *td) #ifdef FIO_SGIO_DEBUG sd->trim_queue_map = calloc(td->o.iodepth, sizeof(int)); #endif - for (i = 0; i < td->o.iodepth; i++) { + for (i = 0, h3p = sd->sgbuf; i < td->o.iodepth; i++, ++h3p) { sd->trim_queues[i] = calloc(1, sizeof(struct sgio_trim)); st = sd->trim_queues[i]; st->unmap_param = calloc(td->o.iodepth + 1, sizeof(char[16])); st->unmap_range_count = 0; st->trim_io_us = calloc(td->o.iodepth, sizeof(struct io_u *)); + h3p->interface_id = 'S'; } td->io_ops_data = sd; diff --git a/fio.1 b/fio.1 index d477b508..9636a85f 100644 --- a/fio.1 +++ b/fio.1 @@ -2114,6 +2114,16 @@ client and the server or in certain loopback configurations. Specify stat system call type to measure lookup/getattr performance. Default is \fBstat\fR for \fBstat\fR\|(2). .TP +.BI (sg)hipri +If this option is set, fio will attempt to use polled IO completions. This +will have a similar effect as (io_uring)hipri. Only SCSI READ and WRITE +commands will have the SGV4_FLAG_HIPRI set (not UNMAP (trim) nor VERIFY). +Older versions of the Linux sg driver that do not support hipri will simply +ignore this flag and do normal IO. The Linux SCSI Low Level Driver (LLD) +that "owns" the device also needs to support hipri (also known as iopoll +and mq_poll). The MegaRAID driver is an example of a SCSI LLD. +Default: clear (0) which does normal (interrupted based) IO. +.TP .BI (sg)readfua \fR=\fPbool With readfua option set to 1, read operations include the force unit access (fua) flag. Default: 0. -- 2.25.1