Messages in this thread | | | Date | Wed, 12 May 2004 14:03:24 -0700 (PDT) | From | Sridhar Samudrala <> | Subject | Re: MSEC_TO_JIFFIES is messed up... |
| |
I have submitted a patch just to do this some time back on netdev mailing list. You can find it at http://marc.theaimsgroup.com/?l=linux-netdev&m=108024598716537&w=2
static inline unsigned long msecs_to_jiffies(unsigned long msecs) { #if 1000 % HZ == 0 return msecs / (1000 / HZ); #elif HZ % 1000 == 0 return msecs * (HZ / 1000); #else return (msecs / 1000) * HZ + (msecs % 1000) * HZ / 1000; #endif }
static inline unsigned long jiffies_to_msecs(unsigned long jiffs) { #if 1000 % HZ == 0 return jiffs * (1000 / HZ); #elif HZ % 1000 == 0 return jiffs / (HZ / 1000); #else return (jiffs / HZ) * 1000 + (jiffs % HZ) * 1000 / HZ; #endif }
I was told that some users of these routines need an explicit roundup of delays. For ex: when HZ=100 and msecs is less than 10, the above msecs_to_jiffies() returns 0 jiffies, whereas some users expect 1 jiffy.
So i modified msecs_to_jiffies() as follows which should do proper rounding when HZ=100. But didn't get back any response.
static inline unsigned long msecs_to_jiffies(unsigned long msecs) { #if 1000 % HZ == 0 return (msecs + ((1000 / HZ) - 1)) / (1000 / HZ); #elif HZ % 1000 == 0 return msecs * (HZ / 1000); #else return (msecs / 1000) * HZ + (msecs % 1000) * HZ / 1000; #endif }
Thanks Sridhar
On Wed, 12 May 2004, Andrew Morton wrote:
> Jeff Garzik <jgarzik@pobox.com> wrote: > > > > > How about we do: > > > > > > #if HZ=1000 > > > #define MSEC_TO_JIFFIES(msec) (msec) > > > #define JIFFIES_TO_MESC(jiffies) (jiffies) > > > #elif HZ=100 > > > #define MSEC_TO_JIFFIES(msec) (msec * 10) > > > #define JIFFIES_TO_MESC(jiffies) (jiffies / 10) > > > #else > > > #define MSEC_TO_JIFFIES(msec) ((HZ * (msec) + 999) / 1000) > > > #define JIFFIES_TO_MSEC(jiffies) ... > > > #endif > > > > > > in some kernel-wide header then kill off all the private implementations? > > > > > > include/linux/time.h. One of the SCTP people already did this, but I > > suppose it's straightforward to reproduce. > > OK, I'll do it. > > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |