| Message ID | 20180921172310.10068-3-lbloch@janustech.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Take the image size into account when allocating the L2 cache | expand |
On Fri 21 Sep 2018 07:23:03 PM CEST, Leonid Bloch wrote: > Adding a lookup table for the powers of two, with the appropriate size > prefixes. This is needed when a size has to be stringified, in which > case something like '(1 * KiB)' would become a literal '(1 * (1L << 10))' > string. Powers of two are used very often for sizes, so such a table > will also make it easier and more intuitive to write them. > > This table is generatred using the following AWK script: > > BEGIN { > suffix="KMGTPE"; > for(i=10; i<64; i++) { > val=2**i; > s=substr(suffix, int(i/10), 1); > n=2**(i%10); > pad=21-int(log(n)/log(10)); > printf("#define S_%d%siB %*d\n", n, s, pad, val); > } > } > > Signed-off-by: Leonid Bloch <lbloch@janustech.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Berto
On 9/21/18 12:23 PM, Leonid Bloch wrote: > Adding a lookup table for the powers of two, with the appropriate size > prefixes. This is needed when a size has to be stringified, in which > case something like '(1 * KiB)' would become a literal '(1 * (1L << 10))' > string. Powers of two are used very often for sizes, so such a table > will also make it easier and more intuitive to write them. Would it be better to provide a generic util function that takes an arbitrary runtime value and converts it to a human-readable form? > --- > include/qemu/units.h | 55 ++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 55 insertions(+) > > diff --git a/include/qemu/units.h b/include/qemu/units.h > index 692db3fbb2..68a7758650 100644 > --- a/include/qemu/units.h > +++ b/include/qemu/units.h > @@ -17,4 +17,59 @@ > #define PiB (INT64_C(1) << 50) > #define EiB (INT64_C(1) << 60) > > +#define S_1KiB 1024 > +#define S_2KiB 2048 These look redundant with the earlier macros while still being limited to compile-time situations, whereas a human-readable converter form will be useful not only for printing compile-time constants, but also beneficial for arbitrary user-provided values.
On 9/24/18 5:09 PM, Eric Blake wrote: > On 9/21/18 12:23 PM, Leonid Bloch wrote: >> Adding a lookup table for the powers of two, with the appropriate size >> prefixes. This is needed when a size has to be stringified, in which >> case something like '(1 * KiB)' would become a literal '(1 * (1L << 10))' >> string. Powers of two are used very often for sizes, so such a table >> will also make it easier and more intuitive to write them. > > Would it be better to provide a generic util function that takes an > arbitrary runtime value and converts it to a human-readable form? > The problem is that the srtingification happens at compile time, and the literal string is written to qcow2.o (the default value). From here comes the need for this table. And the added benefit of it are more concise size notations for power-of-two sizes. Leonid.
diff --git a/include/qemu/units.h b/include/qemu/units.h index 692db3fbb2..68a7758650 100644 --- a/include/qemu/units.h +++ b/include/qemu/units.h @@ -17,4 +17,59 @@ #define PiB (INT64_C(1) << 50) #define EiB (INT64_C(1) << 60) +#define S_1KiB 1024 +#define S_2KiB 2048 +#define S_4KiB 4096 +#define S_8KiB 8192 +#define S_16KiB 16384 +#define S_32KiB 32768 +#define S_64KiB 65536 +#define S_128KiB 131072 +#define S_256KiB 262144 +#define S_512KiB 524288 +#define S_1MiB 1048576 +#define S_2MiB 2097152 +#define S_4MiB 4194304 +#define S_8MiB 8388608 +#define S_16MiB 16777216 +#define S_32MiB 33554432 +#define S_64MiB 67108864 +#define S_128MiB 134217728 +#define S_256MiB 268435456 +#define S_512MiB 536870912 +#define S_1GiB 1073741824 +#define S_2GiB 2147483648 +#define S_4GiB 4294967296 +#define S_8GiB 8589934592 +#define S_16GiB 17179869184 +#define S_32GiB 34359738368 +#define S_64GiB 68719476736 +#define S_128GiB 137438953472 +#define S_256GiB 274877906944 +#define S_512GiB 549755813888 +#define S_1TiB 1099511627776 +#define S_2TiB 2199023255552 +#define S_4TiB 4398046511104 +#define S_8TiB 8796093022208 +#define S_16TiB 17592186044416 +#define S_32TiB 35184372088832 +#define S_64TiB 70368744177664 +#define S_128TiB 140737488355328 +#define S_256TiB 281474976710656 +#define S_512TiB 562949953421312 +#define S_1PiB 1125899906842624 +#define S_2PiB 2251799813685248 +#define S_4PiB 4503599627370496 +#define S_8PiB 9007199254740992 +#define S_16PiB 18014398509481984 +#define S_32PiB 36028797018963968 +#define S_64PiB 72057594037927936 +#define S_128PiB 144115188075855872 +#define S_256PiB 288230376151711744 +#define S_512PiB 576460752303423488 +#define S_1EiB 1152921504606846976 +#define S_2EiB 2305843009213693952 +#define S_4EiB 4611686018427387904 +#define S_8EiB 9223372036854775808 + #endif
Adding a lookup table for the powers of two, with the appropriate size prefixes. This is needed when a size has to be stringified, in which case something like '(1 * KiB)' would become a literal '(1 * (1L << 10))' string. Powers of two are used very often for sizes, so such a table will also make it easier and more intuitive to write them. This table is generatred using the following AWK script: BEGIN { suffix="KMGTPE"; for(i=10; i<64; i++) { val=2**i; s=substr(suffix, int(i/10), 1); n=2**(i%10); pad=21-int(log(n)/log(10)); printf("#define S_%d%siB %*d\n", n, s, pad, val); } } Signed-off-by: Leonid Bloch <lbloch@janustech.com> --- include/qemu/units.h | 55 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+)