diff options
| author | Serapheim Dimitropoulos <[email protected]> | 2020-06-26 18:06:50 -0700 |
|---|---|---|
| committer | GitHub <[email protected]> | 2020-06-26 18:06:50 -0700 |
| commit | ec1fea4516ac2f0c08d31d6308929298d1b281d0 (patch) | |
| tree | 20d1e31cd17d117b5d1d31f750f197e18c82acb3 /config | |
| parent | 7b232e93548a187beb5490314dad181f9ce6b17c (diff) | |
Use percpu_counter for obj_alloc counter of Linux-backed caches
A previous commit enabled the tracking of object allocations
in Linux-backed caches from the SPL layer for debuggability.
The commit is: 9a170fc6fe54f1e852b6c39630fe5ef2bbd97c16
Unfortunately, it also introduced minor performance regressions
that were highlighted by the ZFS perf test-suite. Within Delphix
we found that the regression would be from -1%, all the way up
to -8% for some workloads.
This commit brings performance back up to par by creating a
separate counter for those caches and making it a percpu in
order to avoid lock-contention.
The initial performance testing was done by myself, and the
final round was conducted by @tonynguien who was also the one
that discovered the regression and highlighted the culprit.
Reviewed-by: Matt Ahrens <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Serapheim Dimitropoulos <[email protected]>
Closes #10397
Diffstat (limited to 'config')
| -rw-r--r-- | config/kernel-percpu.m4 | 34 | ||||
| -rw-r--r-- | config/kernel.m4 | 2 |
2 files changed, 36 insertions, 0 deletions
diff --git a/config/kernel-percpu.m4 b/config/kernel-percpu.m4 new file mode 100644 index 000000000..e9654a69e --- /dev/null +++ b/config/kernel-percpu.m4 @@ -0,0 +1,34 @@ +dnl # +dnl # 3.18 API change, +dnl # The function percpu_counter_init now must be passed a GFP mask. +dnl # +AC_DEFUN([ZFS_AC_KERNEL_SRC_PERCPU_COUNTER_INIT], [ + ZFS_LINUX_TEST_SRC([percpu_counter_init_with_gfp], [ + #include <linux/gfp.h> + #include <linux/percpu_counter.h> + ],[ + struct percpu_counter counter; + int error; + + error = percpu_counter_init(&counter, 0, GFP_KERNEL); + ]) +]) + +AC_DEFUN([ZFS_AC_KERNEL_PERCPU_COUNTER_INIT], [ + AC_MSG_CHECKING([whether percpu_counter_init() wants gfp_t]) + ZFS_LINUX_TEST_RESULT([percpu_counter_init_with_gfp], [ + AC_MSG_RESULT(yes) + AC_DEFINE(HAVE_PERCPU_COUNTER_INIT_WITH_GFP, 1, + [percpu_counter_init() wants gfp_t]) + ],[ + AC_MSG_RESULT(no) + ]) +]) + +AC_DEFUN([ZFS_AC_KERNEL_SRC_PERCPU], [ + ZFS_AC_KERNEL_SRC_PERCPU_COUNTER_INIT +]) + +AC_DEFUN([ZFS_AC_KERNEL_PERCPU], [ + ZFS_AC_KERNEL_PERCPU_COUNTER_INIT +]) diff --git a/config/kernel.m4 b/config/kernel.m4 index 78b0ce4d3..ec52f014a 100644 --- a/config/kernel.m4 +++ b/config/kernel.m4 @@ -121,6 +121,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_SRC], [ ZFS_AC_KERNEL_SRC_TOTALRAM_PAGES_FUNC ZFS_AC_KERNEL_SRC_TOTALHIGH_PAGES ZFS_AC_KERNEL_SRC_KSTRTOUL + ZFS_AC_KERNEL_SRC_PERCPU AC_MSG_CHECKING([for available kernel interfaces]) ZFS_LINUX_TEST_COMPILE_ALL([kabi]) @@ -216,6 +217,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_RESULT], [ ZFS_AC_KERNEL_TOTALRAM_PAGES_FUNC ZFS_AC_KERNEL_TOTALHIGH_PAGES ZFS_AC_KERNEL_KSTRTOUL + ZFS_AC_KERNEL_PERCPU ]) dnl # |