dec07fe5d4
Avoid 6 byte hole for padding. Place more frequently used fields
first in an attempt to use just 1 cacheline in the common case.
Before:
```
struct callchain_list {
u64 ip; /* 0 8 */
struct map_symbol ms; /* 8 24 */
struct {
_Bool unfolded; /* 32 1 */
_Bool has_children; /* 33 1 */
}; /* 32 2 */
/* XXX 6 bytes hole, try to pack */
u64 branch_count; /* 40 8 */
u64 from_count; /* 48 8 */
u64 predicted_count; /* 56 8 */
/* --- cacheline 1 boundary (64 bytes) --- */
u64 abort_count; /* 64 8 */
u64 cycles_count; /* 72 8 */
u64 iter_count; /* 80 8 */
u64 iter_cycles; /* 88 8 */
struct branch_type_stat * brtype_stat; /* 96 8 */
const char * srcline; /* 104 8 */
struct list_head list; /* 112 16 */
/* size: 128, cachelines: 2, members: 13 */
/* sum members: 122, holes: 1, sum holes: 6 */
};
```
After:
```
struct callchain_list {
struct list_head list; /* 0 16 */
u64 ip; /* 16 8 */
struct map_symbol ms; /* 24 24 */
const char * srcline; /* 48 8 */
u64 branch_count; /* 56 8 */
/* --- cacheline 1 boundary (64 bytes) --- */
u64 from_count; /* 64 8 */
u64 cycles_count; /* 72 8 */
u64 iter_count; /* 80 8 */
u64 iter_cycles; /* 88 8 */
struct branch_type_stat * brtype_stat; /* 96 8 */
u64 predicted_count; /* 104 8 */
u64 abort_count; /* 112 8 */
struct {
_Bool unfolded; /* 120 1 */
_Bool has_children; /* 121 1 */
}; /* 120 2 */
/* size: 128, cachelines: 2, members: 13 */
/* padding: 6 */
};
```
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: James Clark <james.clark@arm.com>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: liuwenyu <liuwenyu7@huawei.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/r/20231024222353.3024098-11-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.