From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:43974 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726822AbeJCDzA (ORCPT ); Tue, 2 Oct 2018 23:55:00 -0400 Date: Tue, 2 Oct 2018 17:09:40 -0400 From: Steven Rostedt To: Yordan Karadzhov Cc: linux-trace-devel@vger.kernel.org, "Yordan Karadzhov (VMware)" Subject: Re: [PATCH v2 2/5] kernel-shark-qt: Add kshark_convert_nano() function Message-ID: <20181002170940.6261fd8a@gandalf.local.home> In-Reply-To: <20181001135921.32379-3-ykaradzhov@vmware.com> References: <20181001135921.32379-1-ykaradzhov@vmware.com> <20181001135921.32379-3-ykaradzhov@vmware.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-trace-devel-owner@vger.kernel.org List-ID: On Mon, 1 Oct 2018 16:59:18 +0300 Yordan Karadzhov wrote: > From: "Yordan Karadzhov (VMware)" > > kshark_convert_nano() is used to convert the original value of the > timestamp of the trace records (having nanosecond precision) into two > values representing the time in seconds and milliseconds. > > Signed-off-by: Yordan Karadzhov (VMware) > --- > kernel-shark-qt/src/libkshark.c | 14 ++++++++++++++ > kernel-shark-qt/src/libkshark.h | 2 ++ > 2 files changed, 16 insertions(+) > > diff --git a/kernel-shark-qt/src/libkshark.c b/kernel-shark-qt/src/libkshark.c > index a7983eb..e7ea007 100644 > --- a/kernel-shark-qt/src/libkshark.c > +++ b/kernel-shark-qt/src/libkshark.c > @@ -1073,6 +1073,20 @@ const char *kshark_get_info_easy(struct kshark_entry *entry) > return info; > } > > +/** > + * @brief Convert the timestamp of the trace record (nanosecond precision) into > + * seconds and microseconds. > + * > + * @param time: Input location for the timestamp. > + * @param sec: Output location for the value of the seconds. > + * @param usec: Output location for the value of the microseconds. > + */ > +void kshark_convert_nano(uint64_t time, uint64_t *sec, uint64_t *usec) > +{ > + *sec = time / 1000000000ULL; > + *usec = (time / 1000) % 1000000; BTW, just a little optimization, as '%' and '/' are very expensive operations, you can remove one by this: { uint64_t s; s = time / 1000000000ULL; *sec = s; *usec = (time - s * 1000000000ULL) / 1000; As '-' and '*' are fast operations. -- Steve > +} > + > /** > * @brief Dump into a string the content of one entry. The function allocates > * a null terminated string and returns a pointer to this string. The > diff --git a/kernel-shark-qt/src/libkshark.h b/kernel-shark-qt/src/libkshark.h > index f00a584..d24ed8c 100644 > --- a/kernel-shark-qt/src/libkshark.h > +++ b/kernel-shark-qt/src/libkshark.h > @@ -160,6 +160,8 @@ const char *kshark_get_event_name_easy(struct kshark_entry *entry); > > const char *kshark_get_info_easy(struct kshark_entry *entry); > > +void kshark_convert_nano(uint64_t time, uint64_t *sec, uint64_t *usec); > + > char* kshark_dump_entry(const struct kshark_entry *entry); > > struct tep_record *kshark_read_at(struct kshark_context *kshark_ctx,