| Message ID | 20241218092435.21671-1-mengferry@linux.alibaba.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | virtio-blk: add io_uring passthrough support. | expand |
On Wed, Dec 18, 2024 at 05:24:32PM +0800, Ferry Meng wrote: > This patchset implements io_uring passthrough surppot in virtio-blk > driver, bypass vfs and part of block layer logic, resulting in lower > submit latency and increased flexibility when utilizing virtio-blk. > > In this version, currently only supports READ/WRITE vec/no-vec operations, > others like discard or zoned ops not considered in. So the userspace-related If WRITE is supported then FLUSH is also required so that written data can be persisted without falling back to another API. > struct is not complicated. > > struct virtblk_uring_cmd { > __u32 type; > __u32 ioprio; > __u64 sector; > /* above is related to out_hdr */ > __u64 data; // user buffer addr or iovec base addr. > __u32 data_len; // user buffer length or iovec count. > __u32 flag; // only contains whether a vector rw or not. > }; > > To test this patch series, I changed fio's code: > 1. Added virtio-blk support to engines/io_uring.c. > 2. Added virtio-blk support to the t/io_uring.c testing tool. > Link: https://github.com/jdmfr/fio > > > =========== > Performance > =========== > > Using t/io_uring-vblk, the performance of virtio-blk based on uring-cmd > scales better than block device access. (such as below, Virtio-Blk with QEMU, > 1-depth fio) > (passthru) read: IOPS=17.2k, BW=67.4MiB/s (70.6MB/s) > slat (nsec): min=2907, max=43592, avg=3981.87, stdev=595.10 > clat (usec): min=38, max=285,avg=53.47, stdev= 8.28 > lat (usec): min=44, max=288, avg=57.45, stdev= 8.28 > (block) read: IOPS=15.3k, BW=59.8MiB/s (62.7MB/s) > slat (nsec): min=3408, max=35366, avg=5102.17, stdev=790.79 > clat (usec): min=35, max=343, avg=59.63, stdev=10.26 > lat (usec): min=43, max=349, avg=64.73, stdev=10.21 > > Testing the virtio-blk device with fio using 'engines=io_uring_cmd' > and 'engines=io_uring' also demonstrates improvements in submit latency. > (passthru) taskset -c 0 t/io_uring-vblk -b4096 -d8 -c4 -s4 -p0 -F1 -B0 -O0 -n1 -u1 /dev/vdcc0 > IOPS=189.80K, BW=741MiB/s, IOS/call=4/3 > IOPS=187.68K, BW=733MiB/s, IOS/call=4/3 > (block) taskset -c 0 t/io_uring-vblk -b4096 -d8 -c4 -s4 -p0 -F1 -B0 -O0 -n1 -u0 /dev/vdc > IOPS=101.51K, BW=396MiB/s, IOS/call=4/3 > IOPS=100.01K, BW=390MiB/s, IOS/call=4/4 This iodepth=8 (submission/completion batching 4) result surprised me because the io_uring calls are already batched but there is still a 4 microsecond improvement per request. I was expecting to see less improvement when iodepth is increased because the syscall, io_uring, and some block layer cost is amortized thanks to batching and block plugging. Is the virtio-blk driver submitting 4 requests at a time for both passthru and block? I wonder if something else is going on here. > > ======= > Changes > ======= > > Changes in v1: > -------------- > * remove virtblk_is_write() helper > * fix rq_flags type definition (blk_opf_t), add REQ_ALLOC_CACHE flag. > https://lore.kernel.org/io-uring/202412042324.uKQ5KdkE-lkp@intel.com/ > > RFC discussion: > --------------- > https://lore.kernel.org/io-uring/20241203121424.19887-1-mengferry@linux.alibaba.com/ > > Ferry Meng (3): > virtio-blk: add virtio-blk chardev support. > virtio-blk: add uring_cmd support for I/O passthru on chardev. > virtio-blk: add uring_cmd iopoll support. > > drivers/block/virtio_blk.c | 320 +++++++++++++++++++++++++++++++- > include/uapi/linux/virtio_blk.h | 16 ++ > 2 files changed, 331 insertions(+), 5 deletions(-) > > -- > 2.43.5 >
On Wed, Dec 18, 2024 at 05:24:32PM +0800, Ferry Meng wrote: > This patchset implements io_uring passthrough surppot in virtio-blk > driver, bypass vfs and part of block layer logic, resulting in lower > submit latency and increased flexibility when utilizing virtio-blk. Hi, What is the status of this patch series? Stefan > > In this version, currently only supports READ/WRITE vec/no-vec operations, > others like discard or zoned ops not considered in. So the userspace-related > struct is not complicated. > > struct virtblk_uring_cmd { > __u32 type; > __u32 ioprio; > __u64 sector; > /* above is related to out_hdr */ > __u64 data; // user buffer addr or iovec base addr. > __u32 data_len; // user buffer length or iovec count. > __u32 flag; // only contains whether a vector rw or not. > }; > > To test this patch series, I changed fio's code: > 1. Added virtio-blk support to engines/io_uring.c. > 2. Added virtio-blk support to the t/io_uring.c testing tool. > Link: https://github.com/jdmfr/fio > > > =========== > Performance > =========== > > Using t/io_uring-vblk, the performance of virtio-blk based on uring-cmd > scales better than block device access. (such as below, Virtio-Blk with QEMU, > 1-depth fio) > (passthru) read: IOPS=17.2k, BW=67.4MiB/s (70.6MB/s) > slat (nsec): min=2907, max=43592, avg=3981.87, stdev=595.10 > clat (usec): min=38, max=285,avg=53.47, stdev= 8.28 > lat (usec): min=44, max=288, avg=57.45, stdev= 8.28 > (block) read: IOPS=15.3k, BW=59.8MiB/s (62.7MB/s) > slat (nsec): min=3408, max=35366, avg=5102.17, stdev=790.79 > clat (usec): min=35, max=343, avg=59.63, stdev=10.26 > lat (usec): min=43, max=349, avg=64.73, stdev=10.21 > > Testing the virtio-blk device with fio using 'engines=io_uring_cmd' > and 'engines=io_uring' also demonstrates improvements in submit latency. > (passthru) taskset -c 0 t/io_uring-vblk -b4096 -d8 -c4 -s4 -p0 -F1 -B0 -O0 -n1 -u1 /dev/vdcc0 > IOPS=189.80K, BW=741MiB/s, IOS/call=4/3 > IOPS=187.68K, BW=733MiB/s, IOS/call=4/3 > (block) taskset -c 0 t/io_uring-vblk -b4096 -d8 -c4 -s4 -p0 -F1 -B0 -O0 -n1 -u0 /dev/vdc > IOPS=101.51K, BW=396MiB/s, IOS/call=4/3 > IOPS=100.01K, BW=390MiB/s, IOS/call=4/4 > > ======= > Changes > ======= > > Changes in v1: > -------------- > * remove virtblk_is_write() helper > * fix rq_flags type definition (blk_opf_t), add REQ_ALLOC_CACHE flag. > https://lore.kernel.org/io-uring/202412042324.uKQ5KdkE-lkp@intel.com/ > > RFC discussion: > --------------- > https://lore.kernel.org/io-uring/20241203121424.19887-1-mengferry@linux.alibaba.com/ > > Ferry Meng (3): > virtio-blk: add virtio-blk chardev support. > virtio-blk: add uring_cmd support for I/O passthru on chardev. > virtio-blk: add uring_cmd iopoll support. > > drivers/block/virtio_blk.c | 320 +++++++++++++++++++++++++++++++- > include/uapi/linux/virtio_blk.h | 16 ++ > 2 files changed, 331 insertions(+), 5 deletions(-) > > -- > 2.43.5 >
On 2/19/25 10:01 AM, Stefan Hajnoczi wrote: > On Wed, Dec 18, 2024 at 05:24:32PM +0800, Ferry Meng wrote: >> This patchset implements io_uring passthrough surppot in virtio-blk >> driver, bypass vfs and part of block layer logic, resulting in lower >> submit latency and increased flexibility when utilizing virtio-blk. > Hi, > What is the status of this patch series? > > Stefan I apologize for the delayed response. It seems that the maintainer has not yet provided feedback on this patch series, and I was actually waiting for his comments before proceeding. I have received the feedback from the other reviewers & have already discovered some obvious mistakes in v1 series. Although I'm occupied with other tasks recently, I expect to send out v2 patches *in a week*. Thanks. >> In this version, currently only supports READ/WRITE vec/no-vec operations, >> others like discard or zoned ops not considered in. So the userspace-related >> struct is not complicated. >> >> struct virtblk_uring_cmd { >> __u32 type; >> __u32 ioprio; >> __u64 sector; >> /* above is related to out_hdr */ >> __u64 data; // user buffer addr or iovec base addr. >> __u32 data_len; // user buffer length or iovec count. >> __u32 flag; // only contains whether a vector rw or not. >> }; >> >> To test this patch series, I changed fio's code: >> 1. Added virtio-blk support to engines/io_uring.c. >> 2. Added virtio-blk support to the t/io_uring.c testing tool. >> Link: https://github.com/jdmfr/fio >> >> >> =========== >> Performance >> =========== >> >> Using t/io_uring-vblk, the performance of virtio-blk based on uring-cmd >> scales better than block device access. (such as below, Virtio-Blk with QEMU, >> 1-depth fio) >> (passthru) read: IOPS=17.2k, BW=67.4MiB/s (70.6MB/s) >> slat (nsec): min=2907, max=43592, avg=3981.87, stdev=595.10 >> clat (usec): min=38, max=285,avg=53.47, stdev= 8.28 >> lat (usec): min=44, max=288, avg=57.45, stdev= 8.28 >> (block) read: IOPS=15.3k, BW=59.8MiB/s (62.7MB/s) >> slat (nsec): min=3408, max=35366, avg=5102.17, stdev=790.79 >> clat (usec): min=35, max=343, avg=59.63, stdev=10.26 >> lat (usec): min=43, max=349, avg=64.73, stdev=10.21 >> >> Testing the virtio-blk device with fio using 'engines=io_uring_cmd' >> and 'engines=io_uring' also demonstrates improvements in submit latency. >> (passthru) taskset -c 0 t/io_uring-vblk -b4096 -d8 -c4 -s4 -p0 -F1 -B0 -O0 -n1 -u1 /dev/vdcc0 >> IOPS=189.80K, BW=741MiB/s, IOS/call=4/3 >> IOPS=187.68K, BW=733MiB/s, IOS/call=4/3 >> (block) taskset -c 0 t/io_uring-vblk -b4096 -d8 -c4 -s4 -p0 -F1 -B0 -O0 -n1 -u0 /dev/vdc >> IOPS=101.51K, BW=396MiB/s, IOS/call=4/3 >> IOPS=100.01K, BW=390MiB/s, IOS/call=4/4 >> >> ======= >> Changes >> ======= >> >> Changes in v1: >> -------------- >> * remove virtblk_is_write() helper >> * fix rq_flags type definition (blk_opf_t), add REQ_ALLOC_CACHE flag. >> https://lore.kernel.org/io-uring/202412042324.uKQ5KdkE-lkp@intel.com/ >> >> RFC discussion: >> --------------- >> https://lore.kernel.org/io-uring/20241203121424.19887-1-mengferry@linux.alibaba.com/ >> >> Ferry Meng (3): >> virtio-blk: add virtio-blk chardev support. >> virtio-blk: add uring_cmd support for I/O passthru on chardev. >> virtio-blk: add uring_cmd iopoll support. >> >> drivers/block/virtio_blk.c | 320 +++++++++++++++++++++++++++++++- >> include/uapi/linux/virtio_blk.h | 16 ++ >> 2 files changed, 331 insertions(+), 5 deletions(-) >> >> -- >> 2.43.5 >>
On Wed, Feb 26, 2025 at 07:10:36PM +0800, Ferry Meng wrote: > > On 2/19/25 10:01 AM, Stefan Hajnoczi wrote: > > On Wed, Dec 18, 2024 at 05:24:32PM +0800, Ferry Meng wrote: > > > This patchset implements io_uring passthrough surppot in virtio-blk > > > driver, bypass vfs and part of block layer logic, resulting in lower > > > submit latency and increased flexibility when utilizing virtio-blk. > > Hi, > > What is the status of this patch series? > > > > Stefan > > I apologize for the delayed response. It seems that the maintainer has not > yet provided feedback on this patch series, and I was actually waiting for > his comments before proceeding. I have received the feedback from the other > reviewers & have already discovered some obvious mistakes in v1 series. > > > Although I'm occupied with other tasks recently, I expect to send out v2 > patches *in a week*. Great. I'll review the next revision in more detail. Thanks, Stefan > > > Thanks. > > > > In this version, currently only supports READ/WRITE vec/no-vec operations, > > > others like discard or zoned ops not considered in. So the userspace-related > > > struct is not complicated. > > > > > > struct virtblk_uring_cmd { > > > __u32 type; > > > __u32 ioprio; > > > __u64 sector; > > > /* above is related to out_hdr */ > > > __u64 data; // user buffer addr or iovec base addr. > > > __u32 data_len; // user buffer length or iovec count. > > > __u32 flag; // only contains whether a vector rw or not. > > > }; > > > > > > To test this patch series, I changed fio's code: > > > 1. Added virtio-blk support to engines/io_uring.c. > > > 2. Added virtio-blk support to the t/io_uring.c testing tool. > > > Link: https://github.com/jdmfr/fio > > > > > > > > > =========== > > > Performance > > > =========== > > > > > > Using t/io_uring-vblk, the performance of virtio-blk based on uring-cmd > > > scales better than block device access. (such as below, Virtio-Blk with QEMU, > > > 1-depth fio) > > > (passthru) read: IOPS=17.2k, BW=67.4MiB/s (70.6MB/s) > > > slat (nsec): min=2907, max=43592, avg=3981.87, stdev=595.10 > > > clat (usec): min=38, max=285,avg=53.47, stdev= 8.28 > > > lat (usec): min=44, max=288, avg=57.45, stdev= 8.28 > > > (block) read: IOPS=15.3k, BW=59.8MiB/s (62.7MB/s) > > > slat (nsec): min=3408, max=35366, avg=5102.17, stdev=790.79 > > > clat (usec): min=35, max=343, avg=59.63, stdev=10.26 > > > lat (usec): min=43, max=349, avg=64.73, stdev=10.21 > > > > > > Testing the virtio-blk device with fio using 'engines=io_uring_cmd' > > > and 'engines=io_uring' also demonstrates improvements in submit latency. > > > (passthru) taskset -c 0 t/io_uring-vblk -b4096 -d8 -c4 -s4 -p0 -F1 -B0 -O0 -n1 -u1 /dev/vdcc0 > > > IOPS=189.80K, BW=741MiB/s, IOS/call=4/3 > > > IOPS=187.68K, BW=733MiB/s, IOS/call=4/3 > > > (block) taskset -c 0 t/io_uring-vblk -b4096 -d8 -c4 -s4 -p0 -F1 -B0 -O0 -n1 -u0 /dev/vdc > > > IOPS=101.51K, BW=396MiB/s, IOS/call=4/3 > > > IOPS=100.01K, BW=390MiB/s, IOS/call=4/4 > > > > > > ======= > > > Changes > > > ======= > > > > > > Changes in v1: > > > -------------- > > > * remove virtblk_is_write() helper > > > * fix rq_flags type definition (blk_opf_t), add REQ_ALLOC_CACHE flag. > > > https://lore.kernel.org/io-uring/202412042324.uKQ5KdkE-lkp@intel.com/ > > > > > > RFC discussion: > > > --------------- > > > https://lore.kernel.org/io-uring/20241203121424.19887-1-mengferry@linux.alibaba.com/ > > > > > > Ferry Meng (3): > > > virtio-blk: add virtio-blk chardev support. > > > virtio-blk: add uring_cmd support for I/O passthru on chardev. > > > virtio-blk: add uring_cmd iopoll support. > > > > > > drivers/block/virtio_blk.c | 320 +++++++++++++++++++++++++++++++- > > > include/uapi/linux/virtio_blk.h | 16 ++ > > > 2 files changed, 331 insertions(+), 5 deletions(-) > > > > > > -- > > > 2.43.5 > > > >
This patchset implements io_uring passthrough surppot in virtio-blk driver, bypass vfs and part of block layer logic, resulting in lower submit latency and increased flexibility when utilizing virtio-blk. In this version, currently only supports READ/WRITE vec/no-vec operations, others like discard or zoned ops not considered in. So the userspace-related struct is not complicated. struct virtblk_uring_cmd { __u32 type; __u32 ioprio; __u64 sector; /* above is related to out_hdr */ __u64 data; // user buffer addr or iovec base addr. __u32 data_len; // user buffer length or iovec count. __u32 flag; // only contains whether a vector rw or not. }; To test this patch series, I changed fio's code: 1. Added virtio-blk support to engines/io_uring.c. 2. Added virtio-blk support to the t/io_uring.c testing tool. Link: https://github.com/jdmfr/fio =========== Performance =========== Using t/io_uring-vblk, the performance of virtio-blk based on uring-cmd scales better than block device access. (such as below, Virtio-Blk with QEMU, 1-depth fio) (passthru) read: IOPS=17.2k, BW=67.4MiB/s (70.6MB/s) slat (nsec): min=2907, max=43592, avg=3981.87, stdev=595.10 clat (usec): min=38, max=285,avg=53.47, stdev= 8.28 lat (usec): min=44, max=288, avg=57.45, stdev= 8.28 (block) read: IOPS=15.3k, BW=59.8MiB/s (62.7MB/s) slat (nsec): min=3408, max=35366, avg=5102.17, stdev=790.79 clat (usec): min=35, max=343, avg=59.63, stdev=10.26 lat (usec): min=43, max=349, avg=64.73, stdev=10.21 Testing the virtio-blk device with fio using 'engines=io_uring_cmd' and 'engines=io_uring' also demonstrates improvements in submit latency. (passthru) taskset -c 0 t/io_uring-vblk -b4096 -d8 -c4 -s4 -p0 -F1 -B0 -O0 -n1 -u1 /dev/vdcc0 IOPS=189.80K, BW=741MiB/s, IOS/call=4/3 IOPS=187.68K, BW=733MiB/s, IOS/call=4/3 (block) taskset -c 0 t/io_uring-vblk -b4096 -d8 -c4 -s4 -p0 -F1 -B0 -O0 -n1 -u0 /dev/vdc IOPS=101.51K, BW=396MiB/s, IOS/call=4/3 IOPS=100.01K, BW=390MiB/s, IOS/call=4/4 ======= Changes ======= Changes in v1: -------------- * remove virtblk_is_write() helper * fix rq_flags type definition (blk_opf_t), add REQ_ALLOC_CACHE flag. https://lore.kernel.org/io-uring/202412042324.uKQ5KdkE-lkp@intel.com/ RFC discussion: --------------- https://lore.kernel.org/io-uring/20241203121424.19887-1-mengferry@linux.alibaba.com/ Ferry Meng (3): virtio-blk: add virtio-blk chardev support. virtio-blk: add uring_cmd support for I/O passthru on chardev. virtio-blk: add uring_cmd iopoll support. drivers/block/virtio_blk.c | 320 +++++++++++++++++++++++++++++++- include/uapi/linux/virtio_blk.h | 16 ++ 2 files changed, 331 insertions(+), 5 deletions(-)