| Message ID | 02e2209f66f18217aa45b8f7caf715f6@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | crimson-osd vs legacy-osd: should the perf difference be already noticeable? | expand |
I watched some of their crimson osd mettings on youtube and they discussed something similar... however I thought they also said that crimson-osd eats less CPU cores during that test. Did it eat less CPU in your test?
On 2020-01-09 14:58, vitalif@yourcmc.ru wrote: > I watched some of their crimson osd mettings on youtube and they > discussed something similar... Could you please share the link? > however I thought they also said that > crimson-osd eats less CPU cores during that test. Did it eat less CPU > in your test? Hm, I can't prove even that. So here is the output of pidstat while rbd.fio is running, 4k block only: legacy-osd [roman@dell ~]$ pidstat 1 -p 109930 Linux 5.3.13-arch1-1 (dell) 01/09/2020 _x86_64_ (8 CPU) 03:51:49 PM UID PID %usr %system %guest %wait %CPU CPU Command 03:51:51 PM 1000 109930 14.00 8.00 0.00 0.00 22.00 1 ceph-osd 03:51:52 PM 1000 109930 40.00 19.00 0.00 0.00 59.00 1 ceph-osd 03:51:53 PM 1000 109930 44.00 17.00 0.00 0.00 61.00 1 ceph-osd 03:51:54 PM 1000 109930 40.00 20.00 0.00 0.00 60.00 1 ceph-osd 03:51:55 PM 1000 109930 39.00 18.00 0.00 0.00 57.00 1 ceph-osd 03:51:56 PM 1000 109930 41.00 20.00 0.00 0.00 61.00 1 ceph-osd 03:51:57 PM 1000 109930 41.00 15.00 0.00 0.00 56.00 1 ceph-osd 03:51:58 PM 1000 109930 42.00 16.00 0.00 0.00 58.00 1 ceph-osd 03:51:59 PM 1000 109930 42.00 15.00 0.00 0.00 57.00 1 ceph-osd 03:52:00 PM 1000 109930 43.00 15.00 0.00 0.00 58.00 1 ceph-osd 03:52:01 PM 1000 109930 24.00 12.00 0.00 0.00 36.00 1 ceph-osd crimson-osd pidstat 1 -p 108141 Linux 5.3.13-arch1-1 (dell) 01/09/2020 _x86_64_ (8 CPU) 03:47:50 PM UID PID %usr %system %guest %wait %CPU CPU Command 03:47:55 PM 1000 108141 67.00 11.00 0.00 0.00 78.00 0 crimson-osd 03:47:56 PM 1000 108141 79.00 12.00 0.00 0.00 91.00 0 crimson-osd 03:47:57 PM 1000 108141 81.00 9.00 0.00 0.00 90.00 0 crimson-osd 03:47:58 PM 1000 108141 78.00 12.00 0.00 0.00 90.00 0 crimson-osd 03:47:59 PM 1000 108141 78.00 12.00 0.00 1.00 90.00 0 crimson-osd 03:48:00 PM 1000 108141 78.00 13.00 0.00 0.00 91.00 0 crimson-osd 03:48:01 PM 1000 108141 79.00 13.00 0.00 0.00 92.00 0 crimson-osd 03:48:02 PM 1000 108141 78.00 12.00 0.00 0.00 90.00 0 crimson-osd 03:48:03 PM 1000 108141 77.00 11.00 0.00 0.00 88.00 0 crimson-osd 03:48:04 PM 1000 108141 79.00 12.00 0.00 1.00 91.00 0 crimson-osd -- Roman
> Could you please share the link? It was here https://www.youtube.com/channel/UCno-Fry25FJ7B4RycCxOtfw/videos but I'm not sure about what video it was. > Hm, I can't prove even that. So here is the output of pidstat while > rbd.fio is running, 4k block only: Yeah... funny :)
+ Radek, Sam, in case they are interested. On Fri, Jan 10, 2020 at 12:18 AM Roman Penyaev <rpenyaev@suse.de> wrote: > > Subject: crimson-osd vs legacy-osd: should the perf difference be > already noticeable? > > Hi folks, > > I was curios to read some early performance benchmarks which compare > crimson-osd vs legacy-osd, but could not find any. So eventually > decided to do my own micro benchmarks in order to test transport > together with PG layer, avoiding any storage costs completely > (no reason to test memcpy of memstore which is the only available > objectstore for crimson). At least recalling all these ad brochures > of seastar which should bring performance on another level by doing > preemption in userspace, the difference should be already there and > visible in numbers. > > And yes I'm aware that crimson is in development, but if basic > functionality is already supported (like write path), then I can > squeeze some numbers. > > For all testing loads I run original rbd.fio, taken from fio/examples/, > of course changing only block size. Since this is a micro benchmark I > run only 1 osd cluster. > > [global] > ioengine=rbd > clientname=admin > pool=rbd > rbdname=fio_test > rw=randwrite > #bs=4k > > [rbd_iodepth32] > iodepth=32 > > > -- Part 1, turn MemStore and cyan_store into null block > > Testing memcpy is not interesting so in order to run any memstore with > 'memstore_debug_omit_block_device_write=true' option set and skip all > writes I have to do a small tweak in order to start osd, namely I still > need to pass small writes and omit big ones which are sent by the > client, > something as the following: > > - if (len > 0 && !local_conf()->memstore_debug_omit_block_device_write) > { > + > + if (len > 0 && > + (!local_conf()->memstore_debug_omit_block_device_write || > + // We still want cluster meta-data to be saved, so pass only > small > + // writes, expecting user writes will be >= 4k. > + len < 4096)) { > > > *** BTW at the bottom you can find the whole patch with all debug > modifications made to deliver these numbers. > > > # legacy-osd, MemStore > > MON=1 MDS=0 OSD=1 MGR=1 ../src/vstart.sh --memstore -n \ > -o 'memstore_debug_omit_block_device_write=true' > > 4k IOPS=42.7k, BW=167MiB/s, Lat=749.18usec > 8k IOPS=40.2k, BW=314MiB/s, Lat=795.03usec > 16k IOPS=37.6k, BW=588MiB/s, Lat=849.12usec > 32k IOPS=32.0k, BW=1000MiB/s, Lat=998.56usec > 64k IOPS=25.5k, BW=1594MiB/s, Lat=1253.99usec > 128k IOPS=17.5k, BW=2188MiB/s, Lat=1826.54usec > 256k IOPS=10.1k, BW=2531MiB/s, Lat=3157.33usec > 512k IOPS=5252, BW=2626MiB/s, Lat=6071.37usec > 1m IOPS=2656, BW=2656MiB/s, Lat=12029.65usec > > > # crimson-osd, cyan_store > > MON=1 MDS=0 OSD=1 MGR=1 ../src/vstart.sh --crimson --memstore -n \ > -o 'memstore_debug_omit_block_device_write=true' > > 4k IOPS=40.2k, BW=157MiB/s, Lat=796.07usec > 8k IOPS=37.1k, BW=290MiB/s, Lat=861.51usec > 16k IOPS=32.9k, BW=514MiB/s, Lat=970.99usec > 32k IOPS=26.1k, BW=815MiB/s, Lat=1225.78usec > 64k IOPS=21.3k, BW=1333MiB/s, Lat=1498.92usec > 128k IOPS=14.4k, BW=1795MiB/s, Lat=2227.07usec > 256k IOPS=6143, BW=1536MiB/s, Lat=5203.70usec > 512k IOPS=3776, BW=1888MiB/s, Lat=8464.79usec > 1m IOPS=1866, BW=1867MiB/s, Lat=17126.36usec > > > First thing that catches my eye is that for small blocks there is no big > difference at all, but as the block increases, crimsons iops starts to that's also our findings. and it's expected. as async messenger uses the same reactor model as seastar does. actually its original implementation was adapted from seastar's socket stream implementation. > decline. Can it be the transport issue? Can be tested as well. because seastar's socket facility reads from the wire with 4K chunk size, while classic OSD's async messenger reads the payload with the size suggested by the header. so when it comes to larger block size, it takes crimson-osd multiple syscalls and memcpy calls to read the request from wire, that's why classic OSD wins in this case. > > > -- Part 2, complete writes immediately, even not leaving the transport > > Would be great to avoid PG logic costs, exactly like we did for > objectstore, > i.e. the following question can be asked "how fast we can handle writes > and > complete them immediately from the transport callback and measure socket > read/write costs?". I introduced new option 'osd_immediate_completions' > and handle it directly from 'OSD::ms_[fast_]dispatch' function replying > with > success just immediately (for details see patch at the bottom). > > > # legacy-osd > > MON=1 MDS=0 OSD=1 MGR=1 ../src/vstart.sh --memstore -n \ > -o 'osd_immediate_completions=true' > > 4k IOPS=59.2k, BW=231MiB/s, Lat=539.68usec > 8k IOPS=55.1k, BW=430MiB/s, Lat=580.44usec > 16k IOPS=50.5k, BW=789MiB/s, Lat=633.03usec > 32k IOPS=44.6k, BW=1394MiB/s, Lat=716.74usec > 64k IOPS=33.5k, BW=2093MiB/s, Lat=954.60usec > 128k IOPS=20.8k, BW=2604MiB/s, Lat=1535.01usec > 256k IOPS=10.6k, BW=2642MiB/s, Lat=3026.19usec > 512k IOPS=5400, BW=2700MiB/s, Lat=5920.86usec > 1m IOPS=2549, BW=2550MiB/s, Lat=12539.40usec > > > # crimson-osd > > MON=1 MDS=0 OSD=1 MGR=1 ../src/vstart.sh --crimson --memstore -n \ > -o 'osd_immediate_completions=true' > > 4k IOPS=60.2k, BW=235MiB/s, Lat=530.95usec > 8k IOPS=52.0k, BW=407MiB/s, Lat=614.21usec > 16k IOPS=47.1k, BW=736MiB/s, Lat=678.41usec > 32k IOPS=37.8k, BW=1180MiB/s, Lat=846.75usec > 64k IOPS=26.6k, BW=1660MiB/s, Lat=1203.51usec > 128k IOPS=15.5k, BW=1936MiB/s, Lat=2064.12usec > 256k IOPS=7506, BW=1877MiB/s, Lat=4259.19usec > 512k IOPS=3941, BW=1971MiB/s, Lat=8112.67usec > 1m IOPS=1785, BW=1786MiB/s, Lat=17896.44usec > > > As a summary I can say that for me is quite surprising not to notice any > iops improvements on crimson side (not to mention the problem with > reading > of big blocks). Since I run only 1 osd on one particular load I admit > the > artificial nature of such tests (thus called micro benchmark), but then > on what cluster scale and what benchmark can I run to see some > improvements > of a new architecture? have you tried to use multiple fio clients to saturate CPU capacity of OSD nodes? > > Roman > > --- > src/common/options.cc | 4 ++++ > src/crimson/os/cyan_store.cc | 6 +++++- > src/crimson/osd/ops_executer.cc | 4 ++-- > src/crimson/osd/osd.cc | 20 ++++++++++++++++++++ > src/os/memstore/MemStore.cc | 6 +++++- > src/osd/OSD.cc | 24 ++++++++++++++++++++++++ > 6 files changed, 60 insertions(+), 4 deletions(-) > > diff --git a/src/common/options.cc b/src/common/options.cc > index d91827c1a803..769666d2955c 100644 > --- a/src/common/options.cc > +++ b/src/common/options.cc > @@ -4234,6 +4234,10 @@ std::vector<Option> get_global_options() { > .set_default(false) > .set_description(""), > > + Option("osd_immediate_completions", Option::TYPE_BOOL, > Option::LEVEL_ADVANCED) > + .set_default(false) > + .set_description(""), > + > // -------------------------- > // bluestore > > diff --git a/src/crimson/os/cyan_store.cc b/src/crimson/os/cyan_store.cc > index f0749cb921f9..c05e0e40b721 100644 > --- a/src/crimson/os/cyan_store.cc > +++ b/src/crimson/os/cyan_store.cc > @@ -463,7 +463,11 @@ int CyanStore::_write(const coll_t& cid, const > ghobject_t& oid, > return -ENOENT; > > ObjectRef o = c->get_or_create_object(oid); > - if (len > 0 && !local_conf()->memstore_debug_omit_block_device_write) > { > + if (len > 0 && > + (!local_conf()->memstore_debug_omit_block_device_write || > + // We still want cluster meta-data to be saved, so pass only > small > + // writes, expecting user writes will be >= 4k. > + len < 4096)) { > const ssize_t old_size = o->get_size(); > o->write(offset, bl); > used_bytes += (o->get_size() - old_size); > diff --git a/src/crimson/osd/ops_executer.cc > b/src/crimson/osd/ops_executer.cc > index 13f6f086c4ea..a76fc6e206d8 100644 > --- a/src/crimson/osd/ops_executer.cc > +++ b/src/crimson/osd/ops_executer.cc > @@ -431,8 +431,8 @@ OpsExecuter::execute_osd_op(OSDOp& osd_op) > > default: > logger().warn("unknown op {}", ceph_osd_op_name(op.op)); > - throw std::runtime_error( > - fmt::format("op '{}' not supported", ceph_osd_op_name(op.op))); > + // Without that `fio examples/rbd.fio` hangs on exit > + throw ceph::osd::operation_not_supported{}; > } > } > > diff --git a/src/crimson/osd/osd.cc b/src/crimson/osd/osd.cc > index ddd8742d1a74..737cc266766e 100644 > --- a/src/crimson/osd/osd.cc > +++ b/src/crimson/osd/osd.cc > @@ -17,6 +17,7 @@ > #include "messages/MOSDOp.h" > #include "messages/MOSDPGLog.h" > #include "messages/MOSDRepOpReply.h" > +#include "messages/MOSDOpReply.h" > #include "messages/MPGStats.h" > > #include "os/Transaction.h" > @@ -881,6 +882,25 @@ seastar::future<> OSD::committed_osd_maps(version_t > first, > seastar::future<> OSD::handle_osd_op(ceph::net::Connection* conn, > Ref<MOSDOp> m) > { > + > + // > + // Immediately complete requests even without leaving the transport > + // > + if (local_conf().get_val<bool>("osd_immediate_completions")) { > + m->finish_decode(); > + > + for (auto op : m->ops) { > + if (op.op.op == CEPH_OSD_OP_WRITE && > + // Complete big writes only > + op.op.extent.length >= 4096) { > + > + auto reply = make_message<MOSDOpReply>(m.get(), 0, > osdmap->get_epoch(), > + CEPH_OSD_FLAG_ACK | > CEPH_OSD_FLAG_ONDISK, true); > + return conn->send(reply); > + } > + } > + } > + > shard_services.start_operation<ClientRequest>( > *this, > conn->get_shared(), > diff --git a/src/os/memstore/MemStore.cc b/src/os/memstore/MemStore.cc > index 05d16edb6cc0..265dc64c808d 100644 > --- a/src/os/memstore/MemStore.cc > +++ b/src/os/memstore/MemStore.cc > @@ -1047,7 +1047,11 @@ int MemStore::_write(const coll_t& cid, const > ghobject_t& oid, > return -ENOENT; > > ObjectRef o = c->get_or_create_object(oid); > - if (len > 0 && !cct->_conf->memstore_debug_omit_block_device_write) { > + if (len > 0 && > + (!cct->_conf->memstore_debug_omit_block_device_write || > + // We still want cluster meta-data to be saved, so pass only > small > + // writes, expecting user writes will be bigger than 4k. > + len < 4096)) { > const ssize_t old_size = o->get_size(); > o->write(offset, bl); > used_bytes += (o->get_size() - old_size); > diff --git a/src/osd/OSD.cc b/src/osd/OSD.cc > index 96aed0b706e3..796bf927126f 100644 > --- a/src/osd/OSD.cc > +++ b/src/osd/OSD.cc > @@ -7223,6 +7223,30 @@ void OSD::ms_fast_dispatch(Message *m) > return; > } > > + // > + // Immediately complete requests even without leaving the transport > + // > + if (g_conf().get_val<bool>("osd_immediate_completions") && > + m->get_type() == CEPH_MSG_OSD_OP) { > + MOSDOp *osdop = static_cast<MOSDOp*>(m); > + > + osdop->finish_decode(); > + > + for (auto op : osdop->ops) { > + if (op.op.op == CEPH_OSD_OP_WRITE && > + // Complete big writes only > + op.op.extent.length >= 4096) { > + MOSDOpReply *reply; > + > + reply = new MOSDOpReply(osdop, 0, osdmap->get_epoch(), > + CEPH_OSD_FLAG_ACK | > CEPH_OSD_FLAG_ONDISK, true); > + osdop->get_connection()->send_message(reply); > + m->put(); > + return; > + } > + } > + } > + > // peering event? > switch (m->get_type()) { > case CEPH_MSG_PING: >
On 2020-01-10 17:18, kefu chai wrote: [skip] >> >> First thing that catches my eye is that for small blocks there is no >> big >> difference at all, but as the block increases, crimsons iops starts to > > that's also our findings. and it's expected. as async messenger uses > the same reactor model as seastar does. actually its original > implementation was adapted from seastar's socket stream > implementation. Hm, regardless of model messenger should not be a bottleneck. Take a look on the results of fio_ceph_messenger load (runs pure messenger), I can squeeze IOPS=89.8k, BW=351MiB/s on 4k block size, iodepth=32. (also good example https://github.com/ceph/ceph/pull/26932 , almost ~200k) With PG layer (memstore_debug_omit_block_device_write=true option) I can reach 40k iops max. Without PG layer (immediate completion from the transport callback, osd_immediate_completions=true) I get almost 60k. Seems that here starts playing costs on client side and these costs prevail. > >> decline. Can it be the transport issue? Can be tested as well. > > because seastar's socket facility reads from the wire with 4K chunk > size, while classic OSD's async messenger reads the payload with the > size suggested by the header. so when it comes to larger block size, > it takes crimson-osd multiple syscalls and memcpy calls to read the > request from wire, that's why classic OSD wins in this case. Do you plan to fix that? > have you tried to use multiple fio clients to saturate CPU capacity of > OSD nodes? Not yet. But regarding CPU I have these numbers: output of pidstat while rbd.fio is running, 4k block only: legacy-osd [roman@dell ~]$ pidstat 1 -p 109930 Linux 5.3.13-arch1-1 (dell) 01/09/2020 _x86_64_ (8 CPU) 03:51:49 PM UID PID %usr %system %guest %wait %CPU CPU Command 03:51:51 PM 1000 109930 14.00 8.00 0.00 0.00 22.00 1 ceph-osd 03:51:52 PM 1000 109930 40.00 19.00 0.00 0.00 59.00 1 ceph-osd 03:51:53 PM 1000 109930 44.00 17.00 0.00 0.00 61.00 1 ceph-osd 03:51:54 PM 1000 109930 40.00 20.00 0.00 0.00 60.00 1 ceph-osd 03:51:55 PM 1000 109930 39.00 18.00 0.00 0.00 57.00 1 ceph-osd 03:51:56 PM 1000 109930 41.00 20.00 0.00 0.00 61.00 1 ceph-osd 03:51:57 PM 1000 109930 41.00 15.00 0.00 0.00 56.00 1 ceph-osd 03:51:58 PM 1000 109930 42.00 16.00 0.00 0.00 58.00 1 ceph-osd 03:51:59 PM 1000 109930 42.00 15.00 0.00 0.00 57.00 1 ceph-osd 03:52:00 PM 1000 109930 43.00 15.00 0.00 0.00 58.00 1 ceph-osd 03:52:01 PM 1000 109930 24.00 12.00 0.00 0.00 36.00 1 ceph-osd crimson-osd [roman@dell ~]$ pidstat 1 -p 108141 Linux 5.3.13-arch1-1 (dell) 01/09/2020 _x86_64_ (8 CPU) 03:47:50 PM UID PID %usr %system %guest %wait %CPU CPU Command 03:47:55 PM 1000 108141 67.00 11.00 0.00 0.00 78.00 0 crimson-osd 03:47:56 PM 1000 108141 79.00 12.00 0.00 0.00 91.00 0 crimson-osd 03:47:57 PM 1000 108141 81.00 9.00 0.00 0.00 90.00 0 crimson-osd 03:47:58 PM 1000 108141 78.00 12.00 0.00 0.00 90.00 0 crimson-osd 03:47:59 PM 1000 108141 78.00 12.00 0.00 1.00 90.00 0 crimson-osd 03:48:00 PM 1000 108141 78.00 13.00 0.00 0.00 91.00 0 crimson-osd 03:48:01 PM 1000 108141 79.00 13.00 0.00 0.00 92.00 0 crimson-osd 03:48:02 PM 1000 108141 78.00 12.00 0.00 0.00 90.00 0 crimson-osd 03:48:03 PM 1000 108141 77.00 11.00 0.00 0.00 88.00 0 crimson-osd 03:48:04 PM 1000 108141 79.00 12.00 0.00 1.00 91.00 0 crimson-osd Seems quite saturated, almost twice more than legacy-osd. Did you see something similar? -- Roman
> -----Original Message----- > From: ceph-devel-owner@vger.kernel.org <ceph-devel-owner@vger.kernel.org> > On Behalf Of Roman Penyaev > Sent: Friday, January 10, 2020 10:54 AM > To: kefu chai <tchaikov@gmail.com> > Cc: Radoslaw Zarzynski <rzarzyns@redhat.com>; Samuel Just > <sjust@redhat.com>; The Esoteric Order of the Squid Cybernetic <ceph- > devel@vger.kernel.org> > Subject: Re: crimson-osd vs legacy-osd: should the perf difference be already > noticeable? > > On 2020-01-10 17:18, kefu chai wrote: > > [skip] > > >> > >> First thing that catches my eye is that for small blocks there is no > >> big difference at all, but as the block increases, crimsons iops > >> starts to > > > > that's also our findings. and it's expected. as async messenger uses > > the same reactor model as seastar does. actually its original > > implementation was adapted from seastar's socket stream > > implementation. > > Hm, regardless of model messenger should not be a bottleneck. Take a look on > the results of fio_ceph_messenger load (runs pure messenger), I can squeeze > IOPS=89.8k, BW=351MiB/s on 4k block size, iodepth=32. > (also good example https://github.com/ceph/ceph/pull/26932 , almost > ~200k) > > With PG layer (memstore_debug_omit_block_device_write=true option) I can > reach 40k iops max. Without PG layer (immediate completion from the > transport callback, osd_immediate_completions=true) I get almost 60k. > > Seems that here starts playing costs on client side and these costs prevail. > > > > >> decline. Can it be the transport issue? Can be tested as well. > > > > because seastar's socket facility reads from the wire with 4K chunk > > size, while classic OSD's async messenger reads the payload with the > > size suggested by the header. so when it comes to larger block size, > > it takes crimson-osd multiple syscalls and memcpy calls to read the > > request from wire, that's why classic OSD wins in this case. > > Do you plan to fix that? > > > have you tried to use multiple fio clients to saturate CPU capacity of > > OSD nodes? > > Not yet. But regarding CPU I have these numbers: > > output of pidstat while rbd.fio is running, 4k block only: > > legacy-osd > > [roman@dell ~]$ pidstat 1 -p 109930 > Linux 5.3.13-arch1-1 (dell) 01/09/2020 _x86_64_ (8 CPU) > > 03:51:49 PM UID PID %usr %system %guest %wait %CPU > CPU Command > 03:51:51 PM 1000 109930 14.00 8.00 0.00 0.00 22.00 > 1 ceph-osd > 03:51:52 PM 1000 109930 40.00 19.00 0.00 0.00 59.00 > 1 ceph-osd > 03:51:53 PM 1000 109930 44.00 17.00 0.00 0.00 61.00 > 1 ceph-osd > 03:51:54 PM 1000 109930 40.00 20.00 0.00 0.00 60.00 > 1 ceph-osd > 03:51:55 PM 1000 109930 39.00 18.00 0.00 0.00 57.00 > 1 ceph-osd > 03:51:56 PM 1000 109930 41.00 20.00 0.00 0.00 61.00 > 1 ceph-osd > 03:51:57 PM 1000 109930 41.00 15.00 0.00 0.00 56.00 > 1 ceph-osd > 03:51:58 PM 1000 109930 42.00 16.00 0.00 0.00 58.00 > 1 ceph-osd > 03:51:59 PM 1000 109930 42.00 15.00 0.00 0.00 57.00 > 1 ceph-osd > 03:52:00 PM 1000 109930 43.00 15.00 0.00 0.00 58.00 > 1 ceph-osd > 03:52:01 PM 1000 109930 24.00 12.00 0.00 0.00 36.00 > 1 ceph-osd > > > crimson-osd > > [roman@dell ~]$ pidstat 1 -p 108141 > Linux 5.3.13-arch1-1 (dell) 01/09/2020 _x86_64_ (8 CPU) > > 03:47:50 PM UID PID %usr %system %guest %wait %CPU > CPU Command > 03:47:55 PM 1000 108141 67.00 11.00 0.00 0.00 78.00 > 0 crimson-osd > 03:47:56 PM 1000 108141 79.00 12.00 0.00 0.00 91.00 > 0 crimson-osd > 03:47:57 PM 1000 108141 81.00 9.00 0.00 0.00 90.00 > 0 crimson-osd > 03:47:58 PM 1000 108141 78.00 12.00 0.00 0.00 90.00 > 0 crimson-osd > 03:47:59 PM 1000 108141 78.00 12.00 0.00 1.00 90.00 > 0 crimson-osd > 03:48:00 PM 1000 108141 78.00 13.00 0.00 0.00 91.00 > 0 crimson-osd > 03:48:01 PM 1000 108141 79.00 13.00 0.00 0.00 92.00 > 0 crimson-osd > 03:48:02 PM 1000 108141 78.00 12.00 0.00 0.00 90.00 > 0 crimson-osd > 03:48:03 PM 1000 108141 77.00 11.00 0.00 0.00 88.00 > 0 crimson-osd > 03:48:04 PM 1000 108141 79.00 12.00 0.00 1.00 91.00 > 0 crimson-osd > > > Seems quite saturated, almost twice more than legacy-osd. Did you see > something similar? Crimson-osd (seastar) use epoll, by default, it will use more cpu capacity,(you can change epoll mode setting to reduce it), add Ma, Jianpeng in the thread since he did more study on it. BTW, by default crimson-osd is one thread, and legacy ceph-osd (3 threads for async messenger, 2x8 threads for osd (SDD), finisher thread etc,) ,so by default setting, it is 1 thread compare to over 10 threads work, it is expected crimson-osd not show obvious difference. you can change the default thread number for legacy ceph-osd(such as thread=1 for each layer to see more difference.) BTW, please use release build to do test. Crimson-osd is aysnc model, if workload is very light, can't take more advantage of it. > > -- > Roman
On 1/10/20 5:28 PM, Liu, Chunmei wrote: > > >> -----Original Message----- >> From: ceph-devel-owner@vger.kernel.org <ceph-devel-owner@vger.kernel.org> >> On Behalf Of Roman Penyaev >> Sent: Friday, January 10, 2020 10:54 AM >> To: kefu chai <tchaikov@gmail.com> >> Cc: Radoslaw Zarzynski <rzarzyns@redhat.com>; Samuel Just >> <sjust@redhat.com>; The Esoteric Order of the Squid Cybernetic <ceph- >> devel@vger.kernel.org> >> Subject: Re: crimson-osd vs legacy-osd: should the perf difference be already >> noticeable? >> >> On 2020-01-10 17:18, kefu chai wrote: >> >> [skip] >> >>>> >>>> First thing that catches my eye is that for small blocks there is no >>>> big difference at all, but as the block increases, crimsons iops >>>> starts to >>> >>> that's also our findings. and it's expected. as async messenger uses >>> the same reactor model as seastar does. actually its original >>> implementation was adapted from seastar's socket stream >>> implementation. >> >> Hm, regardless of model messenger should not be a bottleneck. Take a look on >> the results of fio_ceph_messenger load (runs pure messenger), I can squeeze >> IOPS=89.8k, BW=351MiB/s on 4k block size, iodepth=32. >> (also good example https://github.com/ceph/ceph/pull/26932 , almost >> ~200k) >> >> With PG layer (memstore_debug_omit_block_device_write=true option) I can >> reach 40k iops max. Without PG layer (immediate completion from the >> transport callback, osd_immediate_completions=true) I get almost 60k. >> >> Seems that here starts playing costs on client side and these costs prevail. >> >>> >>>> decline. Can it be the transport issue? Can be tested as well. >>> >>> because seastar's socket facility reads from the wire with 4K chunk >>> size, while classic OSD's async messenger reads the payload with the >>> size suggested by the header. so when it comes to larger block size, >>> it takes crimson-osd multiple syscalls and memcpy calls to read the >>> request from wire, that's why classic OSD wins in this case. >> >> Do you plan to fix that? >> >>> have you tried to use multiple fio clients to saturate CPU capacity of >>> OSD nodes? >> >> Not yet. But regarding CPU I have these numbers: >> >> output of pidstat while rbd.fio is running, 4k block only: >> >> legacy-osd >> >> [roman@dell ~]$ pidstat 1 -p 109930 >> Linux 5.3.13-arch1-1 (dell) 01/09/2020 _x86_64_ (8 CPU) >> >> 03:51:49 PM UID PID %usr %system %guest %wait %CPU >> CPU Command >> 03:51:51 PM 1000 109930 14.00 8.00 0.00 0.00 22.00 >> 1 ceph-osd >> 03:51:52 PM 1000 109930 40.00 19.00 0.00 0.00 59.00 >> 1 ceph-osd >> 03:51:53 PM 1000 109930 44.00 17.00 0.00 0.00 61.00 >> 1 ceph-osd >> 03:51:54 PM 1000 109930 40.00 20.00 0.00 0.00 60.00 >> 1 ceph-osd >> 03:51:55 PM 1000 109930 39.00 18.00 0.00 0.00 57.00 >> 1 ceph-osd >> 03:51:56 PM 1000 109930 41.00 20.00 0.00 0.00 61.00 >> 1 ceph-osd >> 03:51:57 PM 1000 109930 41.00 15.00 0.00 0.00 56.00 >> 1 ceph-osd >> 03:51:58 PM 1000 109930 42.00 16.00 0.00 0.00 58.00 >> 1 ceph-osd >> 03:51:59 PM 1000 109930 42.00 15.00 0.00 0.00 57.00 >> 1 ceph-osd >> 03:52:00 PM 1000 109930 43.00 15.00 0.00 0.00 58.00 >> 1 ceph-osd >> 03:52:01 PM 1000 109930 24.00 12.00 0.00 0.00 36.00 >> 1 ceph-osd >> >> >> crimson-osd >> >> [roman@dell ~]$ pidstat 1 -p 108141 >> Linux 5.3.13-arch1-1 (dell) 01/09/2020 _x86_64_ (8 CPU) >> >> 03:47:50 PM UID PID %usr %system %guest %wait %CPU >> CPU Command >> 03:47:55 PM 1000 108141 67.00 11.00 0.00 0.00 78.00 >> 0 crimson-osd >> 03:47:56 PM 1000 108141 79.00 12.00 0.00 0.00 91.00 >> 0 crimson-osd >> 03:47:57 PM 1000 108141 81.00 9.00 0.00 0.00 90.00 >> 0 crimson-osd >> 03:47:58 PM 1000 108141 78.00 12.00 0.00 0.00 90.00 >> 0 crimson-osd >> 03:47:59 PM 1000 108141 78.00 12.00 0.00 1.00 90.00 >> 0 crimson-osd >> 03:48:00 PM 1000 108141 78.00 13.00 0.00 0.00 91.00 >> 0 crimson-osd >> 03:48:01 PM 1000 108141 79.00 13.00 0.00 0.00 92.00 >> 0 crimson-osd >> 03:48:02 PM 1000 108141 78.00 12.00 0.00 0.00 90.00 >> 0 crimson-osd >> 03:48:03 PM 1000 108141 77.00 11.00 0.00 0.00 88.00 >> 0 crimson-osd >> 03:48:04 PM 1000 108141 79.00 12.00 0.00 1.00 91.00 >> 0 crimson-osd >> >> >> Seems quite saturated, almost twice more than legacy-osd. Did you see >> something similar? > Crimson-osd (seastar) use epoll, by default, it will use more cpu capacity,(you can change epoll mode setting to reduce it), add Ma, Jianpeng in the thread since he did more study on it. > BTW, by default crimson-osd is one thread, and legacy ceph-osd (3 threads for async messenger, 2x8 threads for osd (SDD), finisher thread etc,) ,so by default setting, it is 1 thread compare to over 10 threads work, it is expected crimson-osd not show obvious difference. you can change the default thread number for legacy ceph-osd(such as thread=1 for each layer to see more difference.) > BTW, please use release build to do test. > Crimson-osd is aysnc model, if workload is very light, can't take more advantage of it. >> >> -- >> Roman > FWIW I can drive the classical OSD pretty hard and get around 70-80K IOPS out of a single OSD, but as Kefu says above it will consume a larger number of cores. I do think per-OSD throughput is still important to look at, but the per-OSD efficiency numbers as Radek has been testing (I gathered some for classical OSD a while back for him) are probably going to be more important overall. Mark
diff --git a/src/common/options.cc b/src/common/options.cc index d91827c1a803..769666d2955c 100644 --- a/src/common/options.cc +++ b/src/common/options.cc @@ -4234,6 +4234,10 @@ std::vector<Option> get_global_options() { .set_default(false) .set_description(""), + Option("osd_immediate_completions", Option::TYPE_BOOL, Option::LEVEL_ADVANCED) + .set_default(false) + .set_description(""), + // -------------------------- // bluestore diff --git a/src/crimson/os/cyan_store.cc b/src/crimson/os/cyan_store.cc index f0749cb921f9..c05e0e40b721 100644 --- a/src/crimson/os/cyan_store.cc +++ b/src/crimson/os/cyan_store.cc @@ -463,7 +463,11 @@ int CyanStore::_write(const coll_t& cid, const ghobject_t& oid, return -ENOENT; ObjectRef o = c->get_or_create_object(oid); - if (len > 0 && !local_conf()->memstore_debug_omit_block_device_write) { + if (len > 0 && + (!local_conf()->memstore_debug_omit_block_device_write || + // We still want cluster meta-data to be saved, so pass only small + // writes, expecting user writes will be >= 4k. + len < 4096)) { const ssize_t old_size = o->get_size(); o->write(offset, bl); used_bytes += (o->get_size() - old_size); diff --git a/src/crimson/osd/ops_executer.cc b/src/crimson/osd/ops_executer.cc index 13f6f086c4ea..a76fc6e206d8 100644 --- a/src/crimson/osd/ops_executer.cc +++ b/src/crimson/osd/ops_executer.cc @@ -431,8 +431,8 @@ OpsExecuter::execute_osd_op(OSDOp& osd_op) default: logger().warn("unknown op {}", ceph_osd_op_name(op.op)); - throw std::runtime_error( - fmt::format("op '{}' not supported", ceph_osd_op_name(op.op))); + // Without that `fio examples/rbd.fio` hangs on exit + throw ceph::osd::operation_not_supported{}; } } diff --git a/src/crimson/osd/osd.cc b/src/crimson/osd/osd.cc index ddd8742d1a74..737cc266766e 100644 --- a/src/crimson/osd/osd.cc +++ b/src/crimson/osd/osd.cc @@ -17,6 +17,7 @@ #include "messages/MOSDOp.h" #include "messages/MOSDPGLog.h" #include "messages/MOSDRepOpReply.h" +#include "messages/MOSDOpReply.h" #include "messages/MPGStats.h" #include "os/Transaction.h" @@ -881,6 +882,25 @@ seastar::future<> OSD::committed_osd_maps(version_t first, seastar::future<> OSD::handle_osd_op(ceph::net::Connection* conn, Ref<MOSDOp> m) { + + // + // Immediately complete requests even without leaving the transport + // + if (local_conf().get_val<bool>("osd_immediate_completions")) { + m->finish_decode(); + + for (auto op : m->ops) { + if (op.op.op == CEPH_OSD_OP_WRITE && + // Complete big writes only + op.op.extent.length >= 4096) { + + auto reply = make_message<MOSDOpReply>(m.get(), 0, osdmap->get_epoch(), + CEPH_OSD_FLAG_ACK | CEPH_OSD_FLAG_ONDISK, true); + return conn->send(reply); + } + } + } + shard_services.start_operation<ClientRequest>( *this, conn->get_shared(), diff --git a/src/os/memstore/MemStore.cc b/src/os/memstore/MemStore.cc index 05d16edb6cc0..265dc64c808d 100644 --- a/src/os/memstore/MemStore.cc +++ b/src/os/memstore/MemStore.cc @@ -1047,7 +1047,11 @@ int MemStore::_write(const coll_t& cid, const ghobject_t& oid, return -ENOENT; ObjectRef o = c->get_or_create_object(oid); - if (len > 0 && !cct->_conf->memstore_debug_omit_block_device_write) { + if (len > 0 && + (!cct->_conf->memstore_debug_omit_block_device_write || + // We still want cluster meta-data to be saved, so pass only small + // writes, expecting user writes will be bigger than 4k. + len < 4096)) { const ssize_t old_size = o->get_size(); o->write(offset, bl); used_bytes += (o->get_size() - old_size); diff --git a/src/osd/OSD.cc b/src/osd/OSD.cc index 96aed0b706e3..796bf927126f 100644 --- a/src/osd/OSD.cc +++ b/src/osd/OSD.cc @@ -7223,6 +7223,30 @@ void OSD::ms_fast_dispatch(Message *m) return; } + // + // Immediately complete requests even without leaving the transport + // + if (g_conf().get_val<bool>("osd_immediate_completions") && + m->get_type() == CEPH_MSG_OSD_OP) { + MOSDOp *osdop = static_cast<MOSDOp*>(m); + + osdop->finish_decode(); + + for (auto op : osdop->ops) { + if (op.op.op == CEPH_OSD_OP_WRITE && + // Complete big writes only + op.op.extent.length >= 4096) { + MOSDOpReply *reply; + + reply = new MOSDOpReply(osdop, 0, osdmap->get_epoch(), + CEPH_OSD_FLAG_ACK | CEPH_OSD_FLAG_ONDISK, true); + osdop->get_connection()->send_message(reply); + m->put(); + return; + } + } + } + // peering event? switch (m->get_type()) {
Subject: crimson-osd vs legacy-osd: should the perf difference be already noticeable? Hi folks, I was curios to read some early performance benchmarks which compare crimson-osd vs legacy-osd, but could not find any. So eventually decided to do my own micro benchmarks in order to test transport together with PG layer, avoiding any storage costs completely (no reason to test memcpy of memstore which is the only available objectstore for crimson). At least recalling all these ad brochures of seastar which should bring performance on another level by doing preemption in userspace, the difference should be already there and visible in numbers. And yes I'm aware that crimson is in development, but if basic functionality is already supported (like write path), then I can squeeze some numbers. For all testing loads I run original rbd.fio, taken from fio/examples/, of course changing only block size. Since this is a micro benchmark I run only 1 osd cluster. [global] ioengine=rbd clientname=admin pool=rbd rbdname=fio_test rw=randwrite #bs=4k [rbd_iodepth32] iodepth=32 -- Part 1, turn MemStore and cyan_store into null block Testing memcpy is not interesting so in order to run any memstore with 'memstore_debug_omit_block_device_write=true' option set and skip all writes I have to do a small tweak in order to start osd, namely I still need to pass small writes and omit big ones which are sent by the client, something as the following: - if (len > 0 && !local_conf()->memstore_debug_omit_block_device_write) { + + if (len > 0 && + (!local_conf()->memstore_debug_omit_block_device_write || + // We still want cluster meta-data to be saved, so pass only small + // writes, expecting user writes will be >= 4k. + len < 4096)) { *** BTW at the bottom you can find the whole patch with all debug modifications made to deliver these numbers. # legacy-osd, MemStore MON=1 MDS=0 OSD=1 MGR=1 ../src/vstart.sh --memstore -n \ -o 'memstore_debug_omit_block_device_write=true' 4k IOPS=42.7k, BW=167MiB/s, Lat=749.18usec 8k IOPS=40.2k, BW=314MiB/s, Lat=795.03usec 16k IOPS=37.6k, BW=588MiB/s, Lat=849.12usec 32k IOPS=32.0k, BW=1000MiB/s, Lat=998.56usec 64k IOPS=25.5k, BW=1594MiB/s, Lat=1253.99usec 128k IOPS=17.5k, BW=2188MiB/s, Lat=1826.54usec 256k IOPS=10.1k, BW=2531MiB/s, Lat=3157.33usec 512k IOPS=5252, BW=2626MiB/s, Lat=6071.37usec 1m IOPS=2656, BW=2656MiB/s, Lat=12029.65usec # crimson-osd, cyan_store MON=1 MDS=0 OSD=1 MGR=1 ../src/vstart.sh --crimson --memstore -n \ -o 'memstore_debug_omit_block_device_write=true' 4k IOPS=40.2k, BW=157MiB/s, Lat=796.07usec 8k IOPS=37.1k, BW=290MiB/s, Lat=861.51usec 16k IOPS=32.9k, BW=514MiB/s, Lat=970.99usec 32k IOPS=26.1k, BW=815MiB/s, Lat=1225.78usec 64k IOPS=21.3k, BW=1333MiB/s, Lat=1498.92usec 128k IOPS=14.4k, BW=1795MiB/s, Lat=2227.07usec 256k IOPS=6143, BW=1536MiB/s, Lat=5203.70usec 512k IOPS=3776, BW=1888MiB/s, Lat=8464.79usec 1m IOPS=1866, BW=1867MiB/s, Lat=17126.36usec First thing that catches my eye is that for small blocks there is no big difference at all, but as the block increases, crimsons iops starts to decline. Can it be the transport issue? Can be tested as well. -- Part 2, complete writes immediately, even not leaving the transport Would be great to avoid PG logic costs, exactly like we did for objectstore, i.e. the following question can be asked "how fast we can handle writes and complete them immediately from the transport callback and measure socket read/write costs?". I introduced new option 'osd_immediate_completions' and handle it directly from 'OSD::ms_[fast_]dispatch' function replying with success just immediately (for details see patch at the bottom). # legacy-osd MON=1 MDS=0 OSD=1 MGR=1 ../src/vstart.sh --memstore -n \ -o 'osd_immediate_completions=true' 4k IOPS=59.2k, BW=231MiB/s, Lat=539.68usec 8k IOPS=55.1k, BW=430MiB/s, Lat=580.44usec 16k IOPS=50.5k, BW=789MiB/s, Lat=633.03usec 32k IOPS=44.6k, BW=1394MiB/s, Lat=716.74usec 64k IOPS=33.5k, BW=2093MiB/s, Lat=954.60usec 128k IOPS=20.8k, BW=2604MiB/s, Lat=1535.01usec 256k IOPS=10.6k, BW=2642MiB/s, Lat=3026.19usec 512k IOPS=5400, BW=2700MiB/s, Lat=5920.86usec 1m IOPS=2549, BW=2550MiB/s, Lat=12539.40usec # crimson-osd MON=1 MDS=0 OSD=1 MGR=1 ../src/vstart.sh --crimson --memstore -n \ -o 'osd_immediate_completions=true' 4k IOPS=60.2k, BW=235MiB/s, Lat=530.95usec 8k IOPS=52.0k, BW=407MiB/s, Lat=614.21usec 16k IOPS=47.1k, BW=736MiB/s, Lat=678.41usec 32k IOPS=37.8k, BW=1180MiB/s, Lat=846.75usec 64k IOPS=26.6k, BW=1660MiB/s, Lat=1203.51usec 128k IOPS=15.5k, BW=1936MiB/s, Lat=2064.12usec 256k IOPS=7506, BW=1877MiB/s, Lat=4259.19usec 512k IOPS=3941, BW=1971MiB/s, Lat=8112.67usec 1m IOPS=1785, BW=1786MiB/s, Lat=17896.44usec As a summary I can say that for me is quite surprising not to notice any iops improvements on crimson side (not to mention the problem with reading of big blocks). Since I run only 1 osd on one particular load I admit the artificial nature of such tests (thus called micro benchmark), but then on what cluster scale and what benchmark can I run to see some improvements of a new architecture? Roman --- src/common/options.cc | 4 ++++ src/crimson/os/cyan_store.cc | 6 +++++- src/crimson/osd/ops_executer.cc | 4 ++-- src/crimson/osd/osd.cc | 20 ++++++++++++++++++++ src/os/memstore/MemStore.cc | 6 +++++- src/osd/OSD.cc | 24 ++++++++++++++++++++++++ 6 files changed, 60 insertions(+), 4 deletions(-) case CEPH_MSG_PING: