Changes v4:
- Printing SNC warnings at the start of every test.
- Printing SNC warnings at the end of every relevant test.
- Remove global snc_mode variable, consolidate snc detection functions
into one.
- Correct minor mistakes.
Changes v3:
- Reworked patch 2.
- Changed minor things in patch 1 like function name and made
corrections to the patch message.
Changes v2:
- Removed patches 2 and 3 since now this part will be supported by the
kernel.
Sub-Numa Clustering (SNC) allows splitting CPU cores, caches and memory
into multiple NUMA nodes. When enabled, NUMA-aware applications can
achieve better performance on bigger server platforms.
SNC support in the kernel was merged into x86/cache [1]. With SNC enabled
and kernel support in place all the tests will function normally (aside
from effective cache size). There might be a problem when SNC is enabled
but the system is still using an older kernel version without SNC
support. Currently the only message displayed in that situation is a
guess that SNC might be enabled and is causing issues. That message also
is displayed whenever the test fails on an Intel platform.
Add a mechanism to discover kernel support for SNC which will add more
meaning and certainty to the error message.
Add runtime SNC mode detection and verify how reliable that information
is.
Series was tested on Ice Lake server platforms with SNC disabled, SNC-2
and SNC-4. The tests were also ran with and without kernel support for
SNC.
Series applies cleanly on kselftest/next.
[1] https://lore.kernel.org/all/20240628215619.76401-1-tony.luck@intel.com/
Previous versions of this series:
[v1] https://lore.kernel.org/all/cover.1709721159.git.maciej.wieczor-retman@inte…
[v2] https://lore.kernel.org/all/cover.1715769576.git.maciej.wieczor-retman@inte…
[v3] https://lore.kernel.org/all/cover.1719842207.git.maciej.wieczor-retman@inte…
Maciej Wieczor-Retman (2):
selftests/resctrl: Adjust effective L3 cache size with SNC enabled
selftests/resctrl: Adjust SNC support messages
tools/testing/selftests/resctrl/cat_test.c | 8 ++
tools/testing/selftests/resctrl/cmt_test.c | 10 +-
tools/testing/selftests/resctrl/mba_test.c | 7 +
tools/testing/selftests/resctrl/mbm_test.c | 9 +-
tools/testing/selftests/resctrl/resctrl.h | 7 +
.../testing/selftests/resctrl/resctrl_tests.c | 8 +-
tools/testing/selftests/resctrl/resctrlfs.c | 130 ++++++++++++++++++
7 files changed, 174 insertions(+), 5 deletions(-)
--
2.45.2
Macros needed for 32-bit compilations were hidden behind 64-bit riscv
ifdefs. Fix the 32-bit compilations by moving macros to allow the
memory_layout test to run on 32-bit.
Signed-off-by: Charlie Jenkins <charlie(a)rivosinc.com>
Fixes: 73d05262a2ca ("selftests: riscv: Generalize mm selftests")
---
tools/testing/selftests/riscv/mm/mmap_test.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/riscv/mm/mmap_test.h b/tools/testing/selftests/riscv/mm/mmap_test.h
index 3b29ca3bb3d4..1c3313c201d5 100644
--- a/tools/testing/selftests/riscv/mm/mmap_test.h
+++ b/tools/testing/selftests/riscv/mm/mmap_test.h
@@ -48,11 +48,11 @@ uint32_t random_addresses[] = {
};
#endif
-// Only works on 64 bit
-#if __riscv_xlen == 64
#define PROT (PROT_READ | PROT_WRITE)
#define FLAGS (MAP_PRIVATE | MAP_ANONYMOUS)
+// Only works on 64 bit
+#if __riscv_xlen == 64
/* mmap must return a value that doesn't use more bits than the hint address. */
static inline unsigned long get_max_value(unsigned long input)
{
@@ -80,6 +80,8 @@ static inline unsigned long get_max_value(unsigned long input)
})
#endif /* __riscv_xlen == 64 */
+#define TEST_MMAPS do { } while (0)
+
static inline int memory_layout(void)
{
void *value1 = mmap(NULL, sizeof(int), PROT, FLAGS, 0, 0);
---
base-commit: 8400291e289ee6b2bf9779ff1c83a291501f017b
change-id: 20240807-mmap_tests__fixes-651cc2b5fead
--
- Charlie
Hello all,
This patch series targets a long-standing BPF usability issue - the lack
of general cross-compilation support - by enabling cross-endian usage of
libbpf and bpftool, as well as supporting cross-endian build targets for
selftests/bpf.
Benefits include improved BPF development and testing for embedded systems
based on e.g. big-endian MIPS, more build options e.g for s390x systems,
and better accessibility to the very latest test tools e.g. 'test_progs'.
Initial development and testing used mips64, since this arch makes
switching the build byte-order trivial and is thus very handy for A/B
testing. However, it lacks some key features (bpf2bpf call, kfuncs, etc)
making for poor selftests/bpf coverage.
Final testing takes the kernel and selftests/bpf cross-built from x86_64
to s390x, and runs the result under QEMU/s390x. That same configuration
could also be used on kernel-patches/bpf CI for regression testing endian
support or perhaps load-sharing s390x builds across x86_64 systems.
This thread includes some background regarding testing on QEMU/s390x and
the generally favourable results:
https://lore.kernel.org/bpf/ZsEcsaa3juxxQBUf@kodidev-ubuntu/
Feedback and suggestions are welcome!
Best regards,
Tony
Changelog:
---------
v3 -> v4:
- fix a use-after-free ELF data-handling error causing rare CI failures
- move bswap functions for func/line/core-relo records to internal header
- use bswap functions also for info blobs in light skeleton
v2 -> v3: (feedback from Andrii)
- improve some log and commit message formatting
- restructure BTF.ext endianness safety checks and byte-swapping
- use BTF.ext info record definitions for swapping, require BTF v1
- follow BTF API implementation more closely for BTF.ext
- explicitly reject loading non-native endianness program into kernel
- simplify linker output byte-order setting
- drop redundant safety checks during linking
- simplify endianness macro and improve blob setup code for light skel
- no unexpected test failures after cross-compiling x86_64 -> s390x
v1 -> v2:
- fixed a light skeleton bug causing test_progs 'map_ptr' failure
- simplified some BTF.ext related endianness logic
- remove an 'inline' usage related to CI checkpatch failure
- improve some formatting noted by checkpatch warnings
- unexpected 'test_progs' failures drop 3 -> 2 (x86_64 to s390x cross)
Tony Ambardar (8):
libbpf: Improve log message formatting
libbpf: Fix header comment typos for BTF.ext
libbpf: Fix output .symtab byte-order during linking
libbpf: Support BTF.ext loading and output in either endianness
libbpf: Support opening bpf objects of either endianness
libbpf: Support linking bpf objects of either endianness
libbpf: Support creating light skeleton of either endianness
selftests/bpf: Support cross-endian building
tools/lib/bpf/bpf_gen_internal.h | 1 +
tools/lib/bpf/btf.c | 196 ++++++++++++++++++++++++---
tools/lib/bpf/btf.h | 3 +
tools/lib/bpf/btf_dump.c | 2 +-
tools/lib/bpf/btf_relocate.c | 2 +-
tools/lib/bpf/gen_loader.c | 187 +++++++++++++++++++------
tools/lib/bpf/libbpf.c | 54 ++++++--
tools/lib/bpf/libbpf.map | 2 +
tools/lib/bpf/libbpf_internal.h | 48 ++++++-
tools/lib/bpf/linker.c | 92 ++++++++++---
tools/lib/bpf/relo_core.c | 2 +-
tools/lib/bpf/skel_internal.h | 3 +-
tools/testing/selftests/bpf/Makefile | 7 +-
13 files changed, 502 insertions(+), 97 deletions(-)
--
2.34.1
compile_commands.json is used by clangd[1] to provide code navigation
and completion functionality to editors. See [2] for an example
configuration that includes this functionality for VSCode.
It can currently be built manually when using kunit.py, by running:
./scripts/clang-tools/gen_compile_commands.py -d .kunit
With this change however, it's built automatically so you don't need to
manually keep it up to date.
Unlike the manual approach, having make build the compile_commands.json
means that it appears in the build output tree instead of at the root of
the source tree, so you'll need to add --compile-commands-dir= to your
clangd args for it to be found.
[1] https://clangd.llvm.org/
[2] https://github.com/FlorentRevest/linux-kernel-vscode
Signed-off-by: Brendan Jackman <jackmanb(a)google.com>
---
tools/testing/kunit/kunit_kernel.py | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
index 7254c110ff23..61931c4926fd 100644
--- a/tools/testing/kunit/kunit_kernel.py
+++ b/tools/testing/kunit/kunit_kernel.py
@@ -72,7 +72,8 @@ class LinuxSourceTreeOperations:
raise ConfigError(e.output.decode())
def make(self, jobs: int, build_dir: str, make_options: Optional[List[str]]) -> None:
- command = ['make', 'ARCH=' + self._linux_arch, 'O=' + build_dir, '--jobs=' + str(jobs)]
+ command = ['make', 'all', 'compile_commands.json', 'ARCH=' + self._linux_arch,
+ 'O=' + build_dir, '--jobs=' + str(jobs)]
if make_options:
command.extend(make_options)
if self._cross_compile:
---
base-commit: 3c999d1ae3c75991902a1a7dad0cb62c2a3008b4
change-id: 20240516-kunit-compile-commands-d994074fc2be
Best regards,
--
Brendan Jackman <jackmanb(a)google.com>
From: Joshua Hahn <joshua.hahn6(a)gmail.com>
v1 -> v2: Edited commit messages for clarity.
Niced CPU usage is a metric reported in host-level /prot/stat, but is
not reported in cgroup-level statistics in cpu.stat. However, when a
host contains multiple tasks across different workloads, it becomes
difficult to gauge how much of the task is being spent on niced
processes based on /proc/stat alone, since host-level metrics do not
provide this cgroup-level granularity.
Exposing this metric will allow users to accurately probe the niced CPU
metric for each workload, and make more informed decisions when
directing higher priority tasks.
Joshua Hahn (2):
Tracking cgroup-level niced CPU time
Selftests for niced CPU statistics
include/linux/cgroup-defs.h | 1 +
kernel/cgroup/rstat.c | 16 ++++-
tools/testing/selftests/cgroup/test_cpu.c | 72 +++++++++++++++++++++++
3 files changed, 86 insertions(+), 3 deletions(-)
--
2.43.5
The resctrl selftests for Memory Bandwidth Allocation (MBA) and Memory
Bandwidth Monitoring (MBM) are failing on some (for example [1]) Emerald
Rapids systems. The test failures result from the following two
properties of these systems:
1) Emerald Rapids systems can have up to 320MB L3 cache. The resctrl
MBA and MBM selftests measure memory traffic for which a hardcoded
250MB buffer has been sufficient so far. On platforms with L3 cache
larger than the buffer, the buffer fits in the L3 cache and thus
no/very little memory traffic is generated during the "memory
bandwidth" tests.
2) Some platform features, for example RAS features or memory
performance features that generate memory traffic may drive accesses
that are counted differently by performance counters and MBM
respectively, for instance generating "overhead" traffic which is not
counted against any specific RMID. Until now these counting
differences have always been "in the noise". On Emerald Rapids
systems the maximum MBA throttling (10% memory bandwidth)
throttles memory bandwidth to where memory accesses by these other
platform features push the memory bandwidth difference between
memory controller performance counters and resctrl (MBM) beyond the
tests' hardcoded tolerance.
Make the tests more robust against platform variations:
1) Let the buffer used by memory bandwidth tests be guided by the size
of the L3 cache.
2) Larger buffers require longer initialization time before the buffer can
be used to measurement. Rework the tests to ensure that buffer
initialization is complete before measurements start.
3) Do not compare performance counters and MBM measurements at low
bandwidth. The value of "low" is hardcoded to 750MiB based on
measurements on Emerald Rapids, Sapphire Rapids, and Ice Lake
systems. This limit is not applicable to AMD systems since it
only applies to the MBA and MBM tests that are isolated to Intel.
[1]
https://ark.intel.com/content/www/us/en/ark/products/237261/intel-xeon-plat…
Reinette Chatre (6):
selftests/resctrl: Fix sparse warnings
selftests/resctrl: Ensure measurements skip initialization of default
benchmark
selftests/resctrl: Simplify benchmark parameter passing
selftests/resctrl: Use cache size to determine "fill_buf" buffer size
selftests/resctrl: Do not compare performance counters and resctrl at
low bandwidth
selftests/resctrl: Keep results from first test run
tools/testing/selftests/resctrl/cmt_test.c | 33 +--
tools/testing/selftests/resctrl/fill_buf.c | 19 +-
tools/testing/selftests/resctrl/mba_test.c | 26 +-
tools/testing/selftests/resctrl/mbm_test.c | 25 +-
tools/testing/selftests/resctrl/resctrl.h | 57 +++--
.../testing/selftests/resctrl/resctrl_tests.c | 15 +-
tools/testing/selftests/resctrl/resctrl_val.c | 223 +++++-------------
7 files changed, 152 insertions(+), 246 deletions(-)
--
2.46.0
v24: https://patchwork.kernel.org/project/netdevbpf/list/?series=884556&state=*
====
Changes:
- Fix failing ynl regen error.
- Error path fixes & extack error messages in dmabuf binding.
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v24/
v23: https://patchwork.kernel.org/project/netdevbpf/list/?series=882978&state=*
====
Fixing relatively minor issues called out in v22. (thanks again!)
Mostly code cleanups, extack error messages, and minor reworks. Nothing
major really changed, so the exact changes per commit is called in the
commit messages.
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v23/
v22: https://patchwork.kernel.org/project/netdevbpf/list/?series=881158&state=*
====
v22 aims to resolve the pending issue pointed to in v21, which is the
interaction with xdp. In this series I rebase on top of the minor
refactor which refactors propagating xdp configuration to slave devices:
https://patchwork.kernel.org/project/netdevbpf/list/?series=881994&state=*
I then disable setting xdp on devices using memory providers, and
propagating xdp configuration to devices using memory providers.
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v22/
v21: https://patchwork.kernel.org/project/netdevbpf/list/?series=880735&state=*
====
v20 addressed some comments and resolved a test failure, but introduced
an unfortunate build error with a config edge case I wasn't testing. v21
simply resolves that error.
Major Changes:
- Resolve build error with CONFIG_PAGE_POOL=n && CONFIG_NET=y
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v21/
v20: https://patchwork.kernel.org/project/netdevbpf/list/?series=879373&state=*
====
v20 aims to resolve a couple of bug reports against v19, and addresses
some review comments around the page_pool_check_memory_provider
mechanism.
Major changes:
- Test edge cases such as header split disabled in selftest.
- Change `offset = 0` back to `offset = offset - start` to resolve issue
found in RX path by Taehee (thanks!)
- Address a few comments around page_pool_check_memory_provider() from
Pavel & Jakub.
- Removed some unnecessary includes across various patches in the
series.
- Removed unnecessary EXPORT_SYMBOL(page_pool_mem_providers) (Jakub).
- Fix regression caused by incorrect dev_get_max_mp_channel check, along
with rename (Jakub).
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v20/
v19: https://patchwork.kernel.org/project/netdevbpf/list/?series=876852&state=*
====
v18 got a thorough review (thanks!), and this iteration addresses the
feedback.
Major changes:
- Prevent deactivating mp bound queues.
- Prevent installing xdp on mp bound netdevs, or installing mps on xdp
installed netdevs.
- Fix corner cases in netlink API vis-a-vis missing attributes.
- Iron out the unreadable netmem driver support story. To be honest, the
conversation with Jakub & Pavel got a bit confusing for me. I've
implemented an approach in this set that makes sense to me, and
AFAICT, addresses the requirements. It may be good as-is, or it
may be a conversation starter/continuer. To be honest IMO there
are many ways to skin this cat and I don't see an extremely strong
reason to go for one approach over another. Here is one approach you
may like.
- Don't reset niov dma_addr on allocation & free.
- Add some tests to the selftest that catches some of the issues around
missing netlink attributes or deactivating mp-bound queues.
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v19/
v18: https://patchwork.kernel.org/project/netdevbpf/list/?series=874848&state=*
====
v17 got minor feedback: (a) to beef up the description on patch 1 and (b)
to remove the leading underscores in the header definition.
I applied (a). (b) seems to be against current conventions so I did not
apply before further discussion.
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v17/
v17: https://patchwork.kernel.org/project/netdevbpf/list/?series=869900&state=*
====
v16 also got a very thorough review and some testing (thanks again!).
Thes version addresses all the concerns reported on v15, in terms of
feedback and issues reported.
Major changes:
- Use ASSERT_RTNL.
- Moved around some of the page_pool helpers definitions so I can hide
some netmem helpers in private files as Jakub suggested.
- Don't make every net_iov hold a ref on the binding as Jakub suggested.
- Fix issue reported by Taehee where we access queues after they have
been freed.
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v17/
v16: https://patchwork.kernel.org/project/netdevbpf/list/?series=866353&state=*
====
v15 got a thorough review and some testing, and this version addresses almost
all the feedback. Some more minor comments where the authors said it
could be done later, I left out.
Major changes:
- Addition of dma-buf introspection to page-pool-get and queue-get.
- Fixes to selftests suggested by Taehee.
- Fixes to documentation suggested by Donald.
- A couple of suggestions and fixes to TCP patches by Eric and David.
- Fixes to number assignements suggested by Arnd.
- Use rtnl_lock()ing to guard against queue reconfiguration while the
page_pool initialization is happening. (Jakub).
- Fixes to a few warnings reproduced by Taehee.
- Fixes to dma-buf binding suggested by Taehee and Jakub.
- Fixes to netlink UAPI suggested by Jakub
- Applied a number of Reviewed-bys and Acked-bys (including ones I lost
from v13+).
Full devmem TCP changes including the full GVE driver implementation is
here:
https://github.com/mina/linux/commits/tcpdevmem-v16/
One caveat: Taehee reproduced a KASAN warning and reported it here:
https://lore.kernel.org/netdev/CAMArcTUdCxOBYGF3vpbq=eBvqZfnc44KBaQTN7H-wqd…
I estimate the issue to be minor and easily fixable:
https://lore.kernel.org/netdev/CAHS8izNgaqC--GGE2xd85QB=utUnOHmioCsDd1TNxJW…
I hope to be able to follow up with a fix to net tree as net-next closes
imminently, but if this iteration doesn't make it in, I will repost with
a fix squashed after net-next reopens, no problem.
v15: https://patchwork.kernel.org/project/netdevbpf/list/?series=865481&state=*
====
No material changes in this version, only a fix to linking against
libynl.a from the last version. Per Jakub's instructions I've pulled one
of his patches into this series, and now use the new libynl.a correctly,
I hope.
As usual, the full devmem TCP changes including the full GVE driver
implementation is here:
https://github.com/mina/linux/commits/tcpdevmem-v15/
v14: https://patchwork.kernel.org/project/netdevbpf/list/?series=865135&archive=…
====
No material changes in this version. Only rebase and re-verification on
top of net-next. v13, I think, raced with commit ebad6d0334793
("net/ipv4: Use nested-BH locking for ipv4_tcp_sk.") being merged to
net-next that caused a patchwork failure to apply. This series should
apply cleanly on commit c4532232fa2a4 ("selftests: net: remove unneeded
IP_GRE config").
I did not wait the customary 24hr as Jakub said it's OK to repost as soon
as I build test the rebased version:
https://lore.kernel.org/netdev/20240625075926.146d769d@kernel.org/
v13: https://patchwork.kernel.org/project/netdevbpf/list/?series=861406&archive=…
====
Major changes:
--------------
This iteration addresses Pavel's review comments, applies his
reviewed-by's, and seeks to fix the patchwork build error (sorry!).
As usual, the full devmem TCP changes including the full GVE driver
implementation is here:
https://github.com/mina/linux/commits/tcpdevmem-v13/
v12: https://patchwork.kernel.org/project/netdevbpf/list/?series=859747&state=*
====
Major changes:
--------------
This iteration only addresses one minor comment from Pavel with regards
to the trace printing of netmem, and the patchwork build error
introduced in v11 because I missed doing an allmodconfig build, sorry.
Other than that v11, AFAICT, received no feedback. There is one
discussion about how the specifics of plugging io uring memory through
the page pool, but not relevant to content in this particular patchset,
AFAICT.
As usual, the full devmem TCP changes including the full GVE driver
implementation is here:
https://github.com/mina/linux/commits/tcpdevmem-v12/
v11: https://patchwork.kernel.org/project/netdevbpf/list/?series=857457&state=*
====
Major Changes:
--------------
v11 addresses feedback received in v10. The major change is the removal
of the memory provider ops as requested by Christoph. We still
accomplish the same thing, but utilizing direct function calls with if
statements rather than generic ops.
Additionally address sparse warnings, bugs and review comments from
folks that reviewed.
As usual, the full devmem TCP changes including the full GVE driver
implementation is here:
https://github.com/mina/linux/commits/tcpdevmem-v11/
Detailed changelog:
-------------------
- Fixes in netdev_rx_queue_restart() from Pavel & David.
- Remove commit e650e8c3a36f5 ("net: page_pool: create hooks for
custom page providers") from the series to address Christoph's
feedback and rebased other patches on the series on this change.
- Fixed build errors with CONFIG_DMA_SHARED_BUFFER &&
!CONFIG_GENERIC_ALLOCATOR build.
- Fixed sparse warnings pointed out by Paolo.
- Drop unnecessary gro_pull_from_frag0 checks.
- Added Bagas reviewed-by to docs.
v10: https://patchwork.kernel.org/project/netdevbpf/list/?series=852422&state=*
====
Major Changes:
--------------
v9 was sent right before the merge window closed (sorry!). v10 is almost
a re-send of the series now that the merge window re-opened. Only
rebased to latest net-next and addressed some minor iterative comments
received on v9.
As usual, the full devmem TCP changes including the full GVE driver
implementation is here:
https://github.com/mina/linux/commits/tcpdevmem-v10/
Detailed changelog:
-------------------
- Fixed tokens leaking in DONTNEED setsockopt (Nikolay).
- Moved net_iov_dma_addr() to devmem.c and made it a devmem specific
helpers (David).
- Rename hook alloc_pages to alloc_netmems as alloc_pages is now
preprocessor macro defined and causes a build error.
v9:
===
Major Changes:
--------------
GVE queue API has been merged. Submitting this version as non-RFC after
rebasing on top of the merged API, and dropped the out of tree queue API
I was carrying on github. Addressed the little feedback v8 has received.
Detailed changelog:
------------------
- Added new patch from David Wei to this series for
netdev_rx_queue_restart()
- Fixed sparse error.
- Removed CONFIG_ checks in netmem_is_net_iov()
- Flipped skb->readable to skb->unreadable
- Minor fixes to selftests & docs.
RFC v8:
=======
Major Changes:
--------------
- Fixed build error generated by patch-by-patch build.
- Applied docs suggestions from Randy.
RFC v7:
=======
Major Changes:
--------------
This revision largely rebases on top of net-next and addresses the feedback
RFCv6 received from folks, namely Jakub, Yunsheng, Arnd, David, & Pavel.
The series remains in RFC because the queue-API ndos defined in this
series are not yet implemented. I have a GVE implementation I carry out
of tree for my testing. A upstreamable GVE implementation is in the
works. Aside from that, in my estimation all the patches are ready for
review/merge. Please do take a look.
As usual the full devmem TCP changes including the full GVE driver
implementation is here:
https://github.com/mina/linux/commits/tcpdevmem-v7/
Detailed changelog:
- Use admin-perm in netlink API.
- Addressed feedback from Jakub with regards to netlink API
implementation.
- Renamed devmem.c functions to something more appropriate for that
file.
- Improve the performance seen through the page_pool benchmark.
- Fix the value definition of all the SO_DEVMEM_* uapi.
- Various fixes to documentation.
Perf - page-pool benchmark:
---------------------------
Improved performance of bench_page_pool_simple.ko tests compared to v6:
https://pastebin.com/raw/v5dYRg8L
net-next base: 8 cycle fast path.
RFC v6: 10 cycle fast path.
RFC v7: 9 cycle fast path.
RFC v7 with CONFIG_DMA_SHARED_BUFFER disabled: 8 cycle fast path,
same as baseline.
Perf - Devmem TCP benchmark:
---------------------
Perf is about the same regardless of the changes in v7, namely the
removal of the static_branch_unlikely to improve the page_pool benchmark
performance:
189/200gbps bi-directional throughput with RX devmem TCP and regular TCP
TX i.e. ~95% line rate.
RFC v6:
=======
Major Changes:
--------------
This revision largely rebases on top of net-next and addresses the little
feedback RFCv5 received.
The series remains in RFC because the queue-API ndos defined in this
series are not yet implemented. I have a GVE implementation I carry out
of tree for my testing. A upstreamable GVE implementation is in the
works. Aside from that, in my estimation all the patches are ready for
review/merge. Please do take a look.
As usual the full devmem TCP changes including the full GVE driver
implementation is here:
https://github.com/mina/linux/commits/tcpdevmem-v6/
This version also comes with some performance data recorded in the cover
letter (see below changelog).
Detailed changelog:
- Rebased on top of the merged netmem_ref changes.
- Converted skb->dmabuf to skb->readable (Pavel). Pavel's original
suggestion was to remove the skb->dmabuf flag entirely, but when I
looked into it closely, I found the issue that if we remove the flag
we have to dereference the shinfo(skb) pointer to obtain the first
frag to tell whether an skb is readable or not. This can cause a
performance regression if it dirties the cache line when the
shinfo(skb) was not really needed. Instead, I converted the skb->dmabuf
flag into a generic skb->readable flag which can be re-used by io_uring
0-copy RX.
- Squashed a few locking optimizations from Eric Dumazet in the RX path
and the DEVMEM_DONTNEED setsockopt.
- Expanded the tests a bit. Added validation for invalid scenarios and
added some more coverage.
Perf - page-pool benchmark:
---------------------------
bench_page_pool_simple.ko tests with and without these changes:
https://pastebin.com/raw/ncHDwAbn
AFAIK the number that really matters in the perf tests is the
'tasklet_page_pool01_fast_path Per elem'. This one measures at about 8
cycles without the changes but there is some 1 cycle noise in some
results.
With the patches this regresses to 9 cycles with the changes but there
is 1 cycle noise occasionally running this test repeatedly.
Lastly I tried disable the static_branch_unlikely() in
netmem_is_net_iov() check. To my surprise disabling the
static_branch_unlikely() check reduces the fast path back to 8 cycles,
but the 1 cycle noise remains.
Perf - Devmem TCP benchmark:
---------------------
189/200gbps bi-directional throughput with RX devmem TCP and regular TCP
TX i.e. ~95% line rate.
Major changes in RFC v5:
========================
1. Rebased on top of 'Abstract page from net stack' series and used the
new netmem type to refer to LSB set pointers instead of re-using
struct page.
2. Downgraded this series back to RFC and called it RFC v5. This is
because this series is now dependent on 'Abstract page from net
stack'[1] and the queue API. Both are removed from the series to
reduce the patch # and those bits are fairly independent or
pre-requisite work.
3. Reworked the page_pool devmem support to use netmem and for some
more unified handling.
4. Reworked the reference counting of net_iov (renamed from
page_pool_iov) to use pp_ref_count for refcounting.
The full changes including the dependent series and GVE page pool
support is here:
https://github.com/mina/linux/commits/tcpdevmem-rfcv5/
[1] https://patchwork.kernel.org/project/netdevbpf/list/?series=810774
Major changes in v1:
====================
1. Implemented MVP queue API ndos to remove the userspace-visible
driver reset.
2. Fixed issues in the napi_pp_put_page() devmem frag unref path.
3. Removed RFC tag.
Many smaller addressed comments across all the patches (patches have
individual change log).
Full tree including the rest of the GVE driver changes:
https://github.com/mina/linux/commits/tcpdevmem-v1
Changes in RFC v3:
==================
1. Pulled in the memory-provider dependency from Jakub's RFC[1] to make the
series reviewable and mergeable.
2. Implemented multi-rx-queue binding which was a todo in v2.
3. Fix to cmsg handling.
The sticking point in RFC v2[2] was the device reset required to refill
the device rx-queues after the dmabuf bind/unbind. The solution
suggested as I understand is a subset of the per-queue management ops
Jakub suggested or similar:
https://lore.kernel.org/netdev/20230815171638.4c057dcd@kernel.org/
This is not addressed in this revision, because:
1. This point was discussed at netconf & netdev and there is openness to
using the current approach of requiring a device reset.
2. Implementing individual queue resetting seems to be difficult for my
test bed with GVE. My prototype to test this ran into issues with the
rx-queues not coming back up properly if reset individually. At the
moment I'm unsure if it's a mistake in the POC or a genuine issue in
the virtualization stack behind GVE, which currently doesn't test
individual rx-queue restart.
3. Our usecases are not bothered by requiring a device reset to refill
the buffer queues, and we'd like to support NICs that run into this
limitation with resetting individual queues.
My thought is that drivers that have trouble with per-queue configs can
use the support in this series, while drivers that support new netdev
ops to reset individual queues can automatically reset the queue as
part of the dma-buf bind/unbind.
The same approach with device resets is presented again for consideration
with other sticking points addressed.
This proposal includes the rx devmem path only proposed for merge. For a
snapshot of my entire tree which includes the GVE POC page pool support &
device memory support:
https://github.com/torvalds/linux/compare/master...mina:linux:tcpdevmem-v3
[1] https://lore.kernel.org/netdev/f8270765-a27b-6ccf-33ea-cda097168d79@redhat.…
[2] https://lore.kernel.org/netdev/CAHS8izOVJGJH5WF68OsRWFKJid1_huzzUK+hpKbLcL4…
Changes in RFC v2:
==================
The sticking point in RFC v1[1] was the dma-buf pages approach we used to
deliver the device memory to the TCP stack. RFC v2 is a proof-of-concept
that attempts to resolve this by implementing scatterlist support in the
networking stack, such that we can import the dma-buf scatterlist
directly. This is the approach proposed at a high level here[2].
Detailed changes:
1. Replaced dma-buf pages approach with importing scatterlist into the
page pool.
2. Replace the dma-buf pages centric API with a netlink API.
3. Removed the TX path implementation - there is no issue with
implementing the TX path with scatterlist approach, but leaving
out the TX path makes it easier to review.
4. Functionality is tested with this proposal, but I have not conducted
perf testing yet. I'm not sure there are regressions, but I removed
perf claims from the cover letter until they can be re-confirmed.
5. Added Signed-off-by: contributors to the implementation.
6. Fixed some bugs with the RX path since RFC v1.
Any feedback welcome, but specifically the biggest pending questions
needing feedback IMO are:
1. Feedback on the scatterlist-based approach in general.
2. Netlink API (Patch 1 & 2).
3. Approach to handle all the drivers that expect to receive pages from
the page pool (Patch 6).
[1] https://lore.kernel.org/netdev/dfe4bae7-13a0-3c5d-d671-f61b375cb0b4@gmail.c…
[2] https://lore.kernel.org/netdev/CAHS8izPm6XRS54LdCDZVd0C75tA1zHSu6jLVO8nzTLX…
==================
* TL;DR:
Device memory TCP (devmem TCP) is a proposal for transferring data to and/or
from device memory efficiently, without bouncing the data to a host memory
buffer.
* Problem:
A large amount of data transfers have device memory as the source and/or
destination. Accelerators drastically increased the volume of such transfers.
Some examples include:
- ML accelerators transferring large amounts of training data from storage into
GPU/TPU memory. In some cases ML training setup time can be as long as 50% of
TPU compute time, improving data transfer throughput & efficiency can help
improving GPU/TPU utilization.
- Distributed training, where ML accelerators, such as GPUs on different hosts,
exchange data among them.
- Distributed raw block storage applications transfer large amounts of data with
remote SSDs, much of this data does not require host processing.
Today, the majority of the Device-to-Device data transfers the network are
implemented as the following low level operations: Device-to-Host copy,
Host-to-Host network transfer, and Host-to-Device copy.
The implementation is suboptimal, especially for bulk data transfers, and can
put significant strains on system resources, such as host memory bandwidth,
PCIe bandwidth, etc. One important reason behind the current state is the
kernel’s lack of semantics to express device to network transfers.
* Proposal:
In this patch series we attempt to optimize this use case by implementing
socket APIs that enable the user to:
1. send device memory across the network directly, and
2. receive incoming network packets directly into device memory.
Packet _payloads_ go directly from the NIC to device memory for receive and from
device memory to NIC for transmit.
Packet _headers_ go to/from host memory and are processed by the TCP/IP stack
normally. The NIC _must_ support header split to achieve this.
Advantages:
- Alleviate host memory bandwidth pressure, compared to existing
network-transfer + device-copy semantics.
- Alleviate PCIe BW pressure, by limiting data transfer to the lowest level
of the PCIe tree, compared to traditional path which sends data through the
root complex.
* Patch overview:
** Part 1: netlink API
Gives user ability to bind dma-buf to an RX queue.
** Part 2: scatterlist support
Currently the standard for device memory sharing is DMABUF, which doesn't
generate struct pages. On the other hand, networking stack (skbs, drivers, and
page pool) operate on pages. We have 2 options:
1. Generate struct pages for dmabuf device memory, or,
2. Modify the networking stack to process scatterlist.
Approach #1 was attempted in RFC v1. RFC v2 implements approach #2.
** part 3: page pool support
We piggy back on page pool memory providers proposal:
https://github.com/kuba-moo/linux/tree/pp-providers
It allows the page pool to define a memory provider that provides the
page allocation and freeing. It helps abstract most of the device memory
TCP changes from the driver.
** part 4: support for unreadable skb frags
Page pool iovs are not accessible by the host; we implement changes
throughput the networking stack to correctly handle skbs with unreadable
frags.
** Part 5: recvmsg() APIs
We define user APIs for the user to send and receive device memory.
Not included with this series is the GVE devmem TCP support, just to
simplify the review. Code available here if desired:
https://github.com/mina/linux/tree/tcpdevmem
This series is built on top of net-next with Jakub's pp-providers changes
cherry-picked.
* NIC dependencies:
1. (strict) Devmem TCP require the NIC to support header split, i.e. the
capability to split incoming packets into a header + payload and to put
each into a separate buffer. Devmem TCP works by using device memory
for the packet payload, and host memory for the packet headers.
2. (optional) Devmem TCP works better with flow steering support & RSS support,
i.e. the NIC's ability to steer flows into certain rx queues. This allows the
sysadmin to enable devmem TCP on a subset of the rx queues, and steer
devmem TCP traffic onto these queues and non devmem TCP elsewhere.
The NIC I have access to with these properties is the GVE with DQO support
running in Google Cloud, but any NIC that supports these features would suffice.
I may be able to help reviewers bring up devmem TCP on their NICs.
* Testing:
The series includes a udmabuf kselftest that show a simple use case of
devmem TCP and validates the entire data path end to end without
a dependency on a specific dmabuf provider.
** Test Setup
Kernel: net-next with this series and memory provider API cherry-picked
locally.
Hardware: Google Cloud A3 VMs.
NIC: GVE with header split & RSS & flow steering support.
Cc: Pavel Begunkov <asml.silence(a)gmail.com>
Cc: David Wei <dw(a)davidwei.uk>
Cc: Jason Gunthorpe <jgg(a)ziepe.ca>
Cc: Yunsheng Lin <linyunsheng(a)huawei.com>
Cc: Shailend Chand <shailend(a)google.com>
Cc: Harshitha Ramamurthy <hramamurthy(a)google.com>
Cc: Shakeel Butt <shakeel.butt(a)linux.dev>
Cc: Jeroen de Borst <jeroendb(a)google.com>
Cc: Praveen Kaligineedi <pkaligineedi(a)google.com>
Cc: Bagas Sanjaya <bagasdotme(a)gmail.com>
Cc: Steven Rostedt <rostedt(a)goodmis.org>
Cc: Christoph Hellwig <hch(a)infradead.org>
Cc: Nikolay Aleksandrov <razor(a)blackwall.org>
Cc: Taehee Yoo <ap420073(a)gmail.com>
Cc: Donald Hunter <donald.hunter(a)gmail.com>
Mina Almasry (13):
netdev: add netdev_rx_queue_restart()
net: netdev netlink api to bind dma-buf to a net device
netdev: support binding dma-buf to netdevice
netdev: netdevice devmem allocator
page_pool: devmem support
memory-provider: dmabuf devmem memory provider
net: support non paged skb frags
net: add support for skbs with unreadable frags
tcp: RX path for devmem TCP
net: add SO_DEVMEM_DONTNEED setsockopt to release RX frags
net: add devmem TCP documentation
selftests: add ncdevmem, netcat for devmem TCP
netdev: add dmabuf introspection
Documentation/netlink/specs/netdev.yaml | 61 +++
Documentation/networking/devmem.rst | 269 +++++++++++
Documentation/networking/index.rst | 1 +
arch/alpha/include/uapi/asm/socket.h | 6 +
arch/mips/include/uapi/asm/socket.h | 6 +
arch/parisc/include/uapi/asm/socket.h | 6 +
arch/sparc/include/uapi/asm/socket.h | 6 +
include/linux/netdevice.h | 2 +
include/linux/skbuff.h | 61 ++-
include/linux/skbuff_ref.h | 9 +-
include/linux/socket.h | 1 +
include/net/devmem.h | 136 ++++++
include/net/mp_dmabuf_devmem.h | 44 ++
include/net/netdev_rx_queue.h | 5 +
include/net/netmem.h | 163 ++++++-
include/net/page_pool/helpers.h | 39 +-
include/net/page_pool/types.h | 22 +-
include/net/sock.h | 2 +
include/net/tcp.h | 5 +-
include/trace/events/page_pool.h | 12 +-
include/uapi/asm-generic/socket.h | 6 +
include/uapi/linux/netdev.h | 13 +
include/uapi/linux/uio.h | 17 +
net/Kconfig | 5 +
net/core/Makefile | 2 +
net/core/datagram.c | 6 +
net/core/dev.c | 28 +-
net/core/devmem.c | 388 ++++++++++++++++
net/core/gro.c | 3 +-
net/core/netdev-genl-gen.c | 23 +
net/core/netdev-genl-gen.h | 6 +
net/core/netdev-genl.c | 137 +++++-
net/core/netdev_rx_queue.c | 81 ++++
net/core/netmem_priv.h | 31 ++
net/core/page_pool.c | 117 +++--
net/core/page_pool_priv.h | 46 ++
net/core/page_pool_user.c | 31 +-
net/core/skbuff.c | 77 +++-
net/core/sock.c | 68 +++
net/ethtool/common.c | 8 +
net/ipv4/esp4.c | 3 +-
net/ipv4/tcp.c | 261 ++++++++++-
net/ipv4/tcp_input.c | 13 +-
net/ipv4/tcp_ipv4.c | 16 +
net/ipv4/tcp_minisocks.c | 2 +
net/ipv4/tcp_output.c | 5 +-
net/ipv6/esp6.c | 3 +-
net/packet/af_packet.c | 4 +-
net/xdp/xsk_buff_pool.c | 5 +
tools/include/uapi/linux/netdev.h | 13 +
tools/net/ynl/lib/.gitignore | 1 +
tools/testing/selftests/net/.gitignore | 1 +
tools/testing/selftests/net/Makefile | 9 +
tools/testing/selftests/net/ncdevmem.c | 570 ++++++++++++++++++++++++
54 files changed, 2731 insertions(+), 124 deletions(-)
create mode 100644 Documentation/networking/devmem.rst
create mode 100644 include/net/devmem.h
create mode 100644 include/net/mp_dmabuf_devmem.h
create mode 100644 net/core/devmem.c
create mode 100644 net/core/netdev_rx_queue.c
create mode 100644 net/core/netmem_priv.h
create mode 100644 tools/testing/selftests/net/ncdevmem.c
--
2.46.0.469.g59c65b2a67-goog
While kunit/visibility.h is today not included in any generated
kernel documentation, also likely due to the fact that none of the
existing comments are correctly recognized as kernel-doc, but once
we decide to add this header and fix the tool, there will be:
../include/kunit/visibility.h:61: warning: Function parameter or
struct member 'symbol' not described in 'EXPORT_SYMBOL_IF_KUNIT'
Signed-off-by: Michal Wajdeczko <michal.wajdeczko(a)intel.com>
---
Cc: Rae Moar <rmoar(a)google.com>
Cc: David Gow <davidgow(a)google.com>
---
include/kunit/visibility.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/include/kunit/visibility.h b/include/kunit/visibility.h
index 0dfe35feeec6..efff77b58dd6 100644
--- a/include/kunit/visibility.h
+++ b/include/kunit/visibility.h
@@ -22,6 +22,7 @@
* EXPORTED_FOR_KUNIT_TESTING namespace only if CONFIG_KUNIT is
* enabled. Must use MODULE_IMPORT_NS(EXPORTED_FOR_KUNIT_TESTING)
* in test file in order to use symbols.
+ * @symbol: the symbol identifier to export
*/
#define EXPORT_SYMBOL_IF_KUNIT(symbol) EXPORT_SYMBOL_NS(symbol, \
EXPORTED_FOR_KUNIT_TESTING)
--
2.43.0